This file is indexed.

/usr/share/xml/udunits/udunits2-common.xml is in libudunits2-0 2.2.20-1.

This file is owned by root:root, with mode 0o644.

The actual contents of the file can be viewed below.

   1
   2
   3
   4
   5
   6
   7
   8
   9
  10
  11
  12
  13
  14
  15
  16
  17
  18
  19
  20
  21
  22
  23
  24
  25
  26
  27
  28
  29
  30
  31
  32
  33
  34
  35
  36
  37
  38
  39
  40
  41
  42
  43
  44
  45
  46
  47
  48
  49
  50
  51
  52
  53
  54
  55
  56
  57
  58
  59
  60
  61
  62
  63
  64
  65
  66
  67
  68
  69
  70
  71
  72
  73
  74
  75
  76
  77
  78
  79
  80
  81
  82
  83
  84
  85
  86
  87
  88
  89
  90
  91
  92
  93
  94
  95
  96
  97
  98
  99
 100
 101
 102
 103
 104
 105
 106
 107
 108
 109
 110
 111
 112
 113
 114
 115
 116
 117
 118
 119
 120
 121
 122
 123
 124
 125
 126
 127
 128
 129
 130
 131
 132
 133
 134
 135
 136
 137
 138
 139
 140
 141
 142
 143
 144
 145
 146
 147
 148
 149
 150
 151
 152
 153
 154
 155
 156
 157
 158
 159
 160
 161
 162
 163
 164
 165
 166
 167
 168
 169
 170
 171
 172
 173
 174
 175
 176
 177
 178
 179
 180
 181
 182
 183
 184
 185
 186
 187
 188
 189
 190
 191
 192
 193
 194
 195
 196
 197
 198
 199
 200
 201
 202
 203
 204
 205
 206
 207
 208
 209
 210
 211
 212
 213
 214
 215
 216
 217
 218
 219
 220
 221
 222
 223
 224
 225
 226
 227
 228
 229
 230
 231
 232
 233
 234
 235
 236
 237
 238
 239
 240
 241
 242
 243
 244
 245
 246
 247
 248
 249
 250
 251
 252
 253
 254
 255
 256
 257
 258
 259
 260
 261
 262
 263
 264
 265
 266
 267
 268
 269
 270
 271
 272
 273
 274
 275
 276
 277
 278
 279
 280
 281
 282
 283
 284
 285
 286
 287
 288
 289
 290
 291
 292
 293
 294
 295
 296
 297
 298
 299
 300
 301
 302
 303
 304
 305
 306
 307
 308
 309
 310
 311
 312
 313
 314
 315
 316
 317
 318
 319
 320
 321
 322
 323
 324
 325
 326
 327
 328
 329
 330
 331
 332
 333
 334
 335
 336
 337
 338
 339
 340
 341
 342
 343
 344
 345
 346
 347
 348
 349
 350
 351
 352
 353
 354
 355
 356
 357
 358
 359
 360
 361
 362
 363
 364
 365
 366
 367
 368
 369
 370
 371
 372
 373
 374
 375
 376
 377
 378
 379
 380
 381
 382
 383
 384
 385
 386
 387
 388
 389
 390
 391
 392
 393
 394
 395
 396
 397
 398
 399
 400
 401
 402
 403
 404
 405
 406
 407
 408
 409
 410
 411
 412
 413
 414
 415
 416
 417
 418
 419
 420
 421
 422
 423
 424
 425
 426
 427
 428
 429
 430
 431
 432
 433
 434
 435
 436
 437
 438
 439
 440
 441
 442
 443
 444
 445
 446
 447
 448
 449
 450
 451
 452
 453
 454
 455
 456
 457
 458
 459
 460
 461
 462
 463
 464
 465
 466
 467
 468
 469
 470
 471
 472
 473
 474
 475
 476
 477
 478
 479
 480
 481
 482
 483
 484
 485
 486
 487
 488
 489
 490
 491
 492
 493
 494
 495
 496
 497
 498
 499
 500
 501
 502
 503
 504
 505
 506
 507
 508
 509
 510
 511
 512
 513
 514
 515
 516
 517
 518
 519
 520
 521
 522
 523
 524
 525
 526
 527
 528
 529
 530
 531
 532
 533
 534
 535
 536
 537
 538
 539
 540
 541
 542
 543
 544
 545
 546
 547
 548
 549
 550
 551
 552
 553
 554
 555
 556
 557
 558
 559
 560
 561
 562
 563
 564
 565
 566
 567
 568
 569
 570
 571
 572
 573
 574
 575
 576
 577
 578
 579
 580
 581
 582
 583
 584
 585
 586
 587
 588
 589
 590
 591
 592
 593
 594
 595
 596
 597
 598
 599
 600
 601
 602
 603
 604
 605
 606
 607
 608
 609
 610
 611
 612
 613
 614
 615
 616
 617
 618
 619
 620
 621
 622
 623
 624
 625
 626
 627
 628
 629
 630
 631
 632
 633
 634
 635
 636
 637
 638
 639
 640
 641
 642
 643
 644
 645
 646
 647
 648
 649
 650
 651
 652
 653
 654
 655
 656
 657
 658
 659
 660
 661
 662
 663
 664
 665
 666
 667
 668
 669
 670
 671
 672
 673
 674
 675
 676
 677
 678
 679
 680
 681
 682
 683
 684
 685
 686
 687
 688
 689
 690
 691
 692
 693
 694
 695
 696
 697
 698
 699
 700
 701
 702
 703
 704
 705
 706
 707
 708
 709
 710
 711
 712
 713
 714
 715
 716
 717
 718
 719
 720
 721
 722
 723
 724
 725
 726
 727
 728
 729
 730
 731
 732
 733
 734
 735
 736
 737
 738
 739
 740
 741
 742
 743
 744
 745
 746
 747
 748
 749
 750
 751
 752
 753
 754
 755
 756
 757
 758
 759
 760
 761
 762
 763
 764
 765
 766
 767
 768
 769
 770
 771
 772
 773
 774
 775
 776
 777
 778
 779
 780
 781
 782
 783
 784
 785
 786
 787
 788
 789
 790
 791
 792
 793
 794
 795
 796
 797
 798
 799
 800
 801
 802
 803
 804
 805
 806
 807
 808
 809
 810
 811
 812
 813
 814
 815
 816
 817
 818
 819
 820
 821
 822
 823
 824
 825
 826
 827
 828
 829
 830
 831
 832
 833
 834
 835
 836
 837
 838
 839
 840
 841
 842
 843
 844
 845
 846
 847
 848
 849
 850
 851
 852
 853
 854
 855
 856
 857
 858
 859
 860
 861
 862
 863
 864
 865
 866
 867
 868
 869
 870
 871
 872
 873
 874
 875
 876
 877
 878
 879
 880
 881
 882
 883
 884
 885
 886
 887
 888
 889
 890
 891
 892
 893
 894
 895
 896
 897
 898
 899
 900
 901
 902
 903
 904
 905
 906
 907
 908
 909
 910
 911
 912
 913
 914
 915
 916
 917
 918
 919
 920
 921
 922
 923
 924
 925
 926
 927
 928
 929
 930
 931
 932
 933
 934
 935
 936
 937
 938
 939
 940
 941
 942
 943
 944
 945
 946
 947
 948
 949
 950
 951
 952
 953
 954
 955
 956
 957
 958
 959
 960
 961
 962
 963
 964
 965
 966
 967
 968
 969
 970
 971
 972
 973
 974
 975
 976
 977
 978
 979
 980
 981
 982
 983
 984
 985
 986
 987
 988
 989
 990
 991
 992
 993
 994
 995
 996
 997
 998
 999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
<?xml version="1.0" encoding="US-ASCII"?>
<!--
Copyright 2008, 2009 University Corporation for Atmospheric Research

This file is part of the UDUNITS-2 package.  See the file COPYRIGHT
in the top-level source-directory of the package for copying and
redistribution conditions.

Units not accepted for use with the SI.  NB: <name> and <symbol>
elements appear only within <aliases>.
-->
<unit-system>
    <!-- Synonyms for SI Units -->
        <unit>
            <comment>Synonym for SI unit</comment>
            <def>s</def>
            <aliases> <name> <singular>sec</singular> </name> </aliases>
            <definition>unit of time, synonym for second</definition>
        </unit>
        <unit>
            <comment>Synonym for SI unit</comment>
            <def>A</def>
            <aliases> <name> <singular>amp</singular> </name> </aliases>
            <definition>unit of electric current, synonym for ampere</definition>
        </unit>
        <unit>
            <comment>Synonym for SI unit</comment>
            <def>K</def>
            <aliases>
                <symbol comment="DEGREE SIGN">&#xB0;K</symbol>        
                <name>
                    <singular>degree_kelvin</singular>
                    <plural>degrees_kelvin</plural>
                </name>
                <name>
                    <singular>degree_K</singular>
                    <plural>degrees_K</plural>
                </name>
                <name>
                    <singular>degreeK</singular>
                    <plural>degreesK</plural>
                </name>
                <name>
                    <singular>deg_K</singular>
                    <plural>degs_K</plural>
                </name>
                <name>
                    <singular>degK</singular>
                    <plural>degsK</plural>
                </name>
            </aliases>
            <definition>unit of temperature, synonym for kelvin</definition>
        </unit>
        <unit>
            <comment>Synonym for SI unit</comment>
            <def>cd</def>
            <aliases> <name> <singular>candle</singular> </name> </aliases>
            <definition>unit of luminous intensity, synonym for candela</definition>
        </unit>
        <unit>
            <comment>Synonym for SI unit</comment>
            <def>mole</def>
            <aliases> <name> <singular>einstein</singular> </name> </aliases>
            <definition>unit of chemical mass, synonym for mole</definition>
        </unit>
        <unit>
            <comment>Synonym for SI unit</comment>
            <def>Hz</def>
            <aliases>
                <name> <singular>baud</singular> </name>
                <symbol>Bd</symbol>
                <symbol>bps</symbol>
            </aliases>
            <definition>unit of frequency, synonym for hertz</definition>
        </unit>
        <unit>
            <comment>Synonym for SI unit</comment>
            <def>degree_Celsius</def>
            <aliases>
                <symbol comment="DEGREE CELSIUS">&#x2103;</symbol>       
                <name> <singular>celsius</singular> </name>
                <name>
                    <singular>degree_C</singular>
                    <plural>degrees_C</plural>
                </name>
                <name>
                    <singular>degreeC</singular>
                    <plural>degreesC</plural>
                </name>
                <name>
                    <singular>deg_C</singular>
                    <plural>degs_C</plural>
                </name>
                <name>
                    <singular>degC</singular>
                    <plural>degsC</plural>
                </name>
            </aliases>
            <definition>unit of temperature, synonym for 'K @ 273.15' (degree_Celsius)</definition>
        </unit>
        <unit>
            <comment>Synonym for SI unit</comment>
            <def>knot</def>
            <aliases>
                <symbol>kt</symbol>
                <symbol>kts</symbol>
            </aliases>
            <definition>unit of speed, synonym for nautical_mile/hour</definition>
        </unit>

    <!-- Constants -->
        <unit>
            <comment>Constant; value is +-30e15</comment>
            <def>6.02214179e23/mol</def>
            <aliases>
                <name><singular>avogadro_constant</singular></name>
                <noplural/>
            </aliases>
            <definition>number of constituent particles (usually atoms or molecules) per mole of a given substance</definition>
        </unit>
        <unit>
            <comment>Constant</comment>
            <def>0.01</def>
            <aliases>
                <name><singular>percent</singular></name>
                <noplural/>
                <symbol>%</symbol>
            </aliases>
            <definition>number of parts per hundred</definition>
        </unit>
        <unit>
            <comment>Constant</comment>
            <def>1e-6</def>
            <aliases>
                <symbol>ppm</symbol>
                <symbol>ppmv</symbol>
            </aliases>
            <definition>parts per million</definition>
        </unit>
        <unit>
            <comment>Constant</comment>
            <def>1e-9</def>
            <aliases>
                <symbol>ppb</symbol>
                <symbol>ppbv</symbol>
            </aliases>
            <definition>parts per billion</definition>
        </unit>
        <unit>
            <comment>Constant</comment>
            <def>1e-12</def>
            <aliases>
                <symbol>ppt</symbol>
                <symbol>pptv</symbol>
            </aliases>
            <definition>parts per trillion</definition>
        </unit>
        <unit>
            <comment>Constant</comment>
            <def>1e-15</def>
            <aliases>
                <symbol>ppq</symbol>
                <symbol>ppqv</symbol>
            </aliases>
            <definition>parts per quadrillion</definition>
        </unit>

    <!-- Plane Angle -->
        <unit>
            <def>0.9 arc_degree</def>
            <aliases> <name><singular>grade</singular></name> </aliases>
            <definition>1/100 of a right angle (90 degrees)</definition>
        </unit>
        <unit>
            <def>2 pi rad</def>
            <aliases>
                <name><singular>circle</singular></name>
                <name><singular>cycle</singular></name>
                <name><singular>turn</singular></name>
                <name><singular>revolution</singular></name>
                <name><singular>rotation</singular></name>
            </aliases>
            <definition>unit of angle in a plane signifying a full 360-degree circle</definition>
        </unit>
        <unit>
            <def>arc_degree</def>
            <aliases>
                <name>
                    <singular>degree_north</singular>
                    <plural>degrees_north</plural>
                </name>
                <name>
                    <singular>degree_N</singular>
                    <plural>degrees_N</plural>
                </name>
                <name>
                    <singular>degreeN</singular>
                    <plural>degreesN</plural>
                </name>
                <name>
                    <singular>degree_east</singular>
                    <plural>degrees_east</plural>
                </name>
                <name>
                    <singular>degree_E</singular>
                    <plural>degrees_E</plural>
                </name>
                <name>
                    <singular>degreeE</singular>
                    <plural>degreesE</plural>
                </name>
                <name>
                    <singular>degree_true</singular>
                    <plural>degrees_true</plural>
                </name>
                <name>
                    <singular>degree_T</singular>
                    <plural>degrees_T</plural>
                </name>
                <name>
                    <singular>degreeT</singular>
                    <plural>degreesT</plural>
                </name>
            </aliases>
            <definition>unit of angle on a sphere</definition>
        </unit>
        <unit>
            <def>-1 degree_east</def>
            <aliases>
                <name>
                    <singular>degree_west</singular>
                    <plural>degrees_west</plural>
                </name>
                <name>
                    <singular>degree_W</singular>
                    <plural>degrees_W</plural>
                </name>
                <name>
                    <singular>degreeW</singular>
                    <plural>degreesW</plural>
                </name>
            </aliases>
            <definition>unit of angle on a sphere (units for negative direction)</definition>
        </unit>

    <!-- Mass -->
        <unit>
            <def>2.916667e-2 kg</def>
            <aliases>
                <name> <singular>assay_ton</singular> </name>
            </aliases>
            <definition>reference unit of mass for a body of ore; roughly equal to 29167 milligrams</definition>
        </unit>
        <unit>
            <def>2.834952e-2 kg</def>
            <aliases>
                <name> <singular>avoirdupois_ounce</singular> </name>
            </aliases>
            <definition>unit of mass equal to 1/16 avoirdupois pound, commonly used in the United States (16 oz = 1 pound = 7000 grains)</definition>
        </unit>
        <unit>
            <def>4.5359237e-1 kg</def>
            <aliases>
                <name> <singular>avoirdupois_pound</singular> </name>
                <name> <singular>pound</singular> </name>
                <symbol>lb</symbol>
            </aliases>
            <definition>unit of mass in avoirdupois system of weights (a system commonly used in United States)</definition>
        </unit>
        <unit>
            <def>2e-4 kg</def>
            <aliases>
                <name> <singular>carat</singular> </name>
            </aliases>
            <definition>unit of mass equal to 0.2 gram (defined 1907)</definition>
        </unit>
        <unit>
            <def>6.479891e-5 kg</def>
            <aliases>
                <name> <singular>grain</singular> </name>
                <symbol>gr</symbol>
            </aliases>
            <definition>unit of mass equal to 1/7000 pound</definition>
        </unit>
        <unit>
            <def>5.080235e1 kg</def>
            <aliases>
                <name> <singular>long_hundredweight</singular> </name>
            </aliases>
            <definition>unit of mass; a British hundredweight, which is 8 stone * 14 pounds/stone</definition>
        </unit>
        <unit>
            <def>1.555174e-3 kg</def>
            <aliases>
                <name> <singular>pennyweight</singular> </name>
            </aliases>
            <definition>unit of mass; based on historical US troy weight system (is 1/20 troy ounce)</definition>
        </unit>
        <unit>
            <def>4.535924e1 kg</def>
            <aliases>
                <name> <singular>short_hundredweight</singular> </name>
            </aliases>
            <definition>unit of mass, a US hundredweight, which is 100 pounds</definition>
        </unit>
        <unit>
            <def>14.59390 kg</def>
            <aliases>
                <name> <singular>slug</singular> </name>
            </aliases>
            <definition>unit of mass associated with Imperial units; a mass that accelerates by 1 ft/s2 when a force of one pound-force (lbF) is exerted on it</definition>
        </unit>
        <unit>
            <def>3.110348e-2 kg</def>
            <aliases>
                <name> <singular>troy_ounce</singular> </name>
                <name> <singular>apothecary_ounce</singular> </name>
            </aliases>
            <definition>unit of mass; based on historical US troy weight system (is 1/12 troy pound)</definition>
        </unit>
        <unit>
            <def>3.732417e-1 kg</def>
            <aliases>
                <name> <singular>troy_pound</singular> </name>
                <name> <singular>apothecary_pound</singular> </name>
            </aliases>
            <definition>unit of mass; based on historical US troy weight system (is 5760 grain)</definition>
        </unit>
        <unit>
            <def>20 grain</def>
            <aliases> <name> <singular>scruple</singular> </name> </aliases>
            <definition>unit of mass in apothecaries' weight system (is 1/3 apdram)</definition>
        </unit>
        <unit>
            <def>60 grain</def>
            <aliases> <name> <singular>apdram</singular> </name> </aliases>
            <definition>unit of mass in apothecaries' weight system (is 1/8 apounce)</definition>
        </unit>
        <unit>
            <comment>exact</comment>
            <def>avoirdupois_ounce/16</def>
            <aliases>
                <name> <singular>dram</singular> </name>
                <symbol>dr</symbol>
            </aliases>
            <definition>unit of mass in the avoirdupois system (the system commonly used in the United States)</definition>
        </unit>
        <unit>
            <def>480 grain</def>
            <aliases> <name> <singular>apounce</singular> </name> </aliases>
            <definition>unit of mass in apothecaries' weight system (is 1/16 appound)</definition>
        </unit>
        <unit>
            <def>5760 grain</def>
            <aliases> <name> <singular>appound</singular> </name> </aliases>
            <definition>unit of mass in apothecaries' weight system (is same as a troy pound)</definition>
        </unit>
        <unit> 
            <def>94 pound</def>
            <aliases> <name> <singular>bag</singular> </name> </aliases>
            <definition>unit of mass, for a traditional bag of portland cement</definition>
        </unit>
        <unit>
            <def>2000 pound</def>
            <aliases>
                <name> <singular>short_ton</singular> </name>
                <name> <singular>ton</singular> </name>
            </aliases>
            <definition>unit of mass based on US weight system</definition>
        </unit>
        <unit>
            <def>2240 pound</def>
            <aliases>
                <name> <singular>long_ton</singular> </name>
            </aliases>
            <definition>unit of mass based on British imperial weight system</definition>
        </unit>

    <!-- Length -->
        <unit>
            <def>1e-15 m</def>
            <aliases>
                <name> <singular>fermi</singular> </name>
            </aliases>
            <definition>unit of length equal to 10e-15 meters, a typical length-scale of nuclear physics</definition>
        </unit>
        <unit>
            <def>9.46073e15 m</def>
            <aliases>
                <name> <singular>light_year</singular> </name>
            </aliases>
            <definition>unit of length equal to the distance traversed by light in one mean solar year (365.2422 days), a typical length-scale of astronomy</definition>
        </unit>
        <unit>
            <def>1e-6 m</def>
            <aliases>
                <name> <singular>micron</singular> </name>
            </aliases>
            <definition>unit of length, a typical length-scale of technology and science fields</definition>
        </unit>
        <unit>
            <def>2.54e-5 m</def>
            <aliases>
                <name> <singular>mil</singular> </name>
            </aliases>
            <definition>unit of length equal to 0.001 inch, a typical length-scale for measuring wire diameters</definition>
        </unit>
        <unit>
            <def>3.085678e16 m</def>
            <aliases>
                <name> <singular>parsec</singular> </name>
            </aliases>
            <definition>unit of length corresponding to the distance at which the mean radius of the earth's orbit subtends an angle of one second of arc, a typical length-scale of astronomy</definition>
        </unit>
        <unit>
            <def>3.514598e-4 m</def>
            <aliases>
                <name> <singular>printers_point</singular> </name>
            </aliases>
            <definition>unit of length equal to 1/72.27 inch, the original (standardized 1886) unit for measuring font size and other small items on a printed page (see also big_point)</definition>
        </unit>
        <unit>
            <def>2.011684e1 m</def>
            <aliases>
                <name> <singular>chain</singular> </name>
            </aliases>
            <definition>unit of length equal to 66 feet (4 poles), or 1/10 furlong, a typical (historical) scale of land surveying</definition>
        </unit>
        <unit>
            <def>12 printers_point</def>
            <aliases>
                <name> <singular>printers_pica</singular> </name>
                <name> <singular>pica</singular> </name>
            </aliases>
            <definition>unit of length equal to 1/6 inch (12 printers points)</definition>
        </unit>
        <unit>
            <def>nautical_mile</def>
            <aliases>
                <name> <singular>nmile</singular> </name>
            </aliases>
            <definition>unit of length in the US Customary System, equal to 6,076 feet; typically used for air and sea navigation</definition>
        </unit>
        <unit>
            <def>(1200/3937) m</def>
            <aliases>
                <name>
                    <singular>US_survey_foot</singular>
                    <plural>US_survey_feet</plural>
                </name>
            </aliases>
            <definition>unit of length used for earlier survey data in some countries, slightly different than the current international foot</definition>
        </unit>
        <unit>
            <def>3 US_survey_feet</def>
            <aliases>
                <name> <singular>US_survey_yard</singular> </name>
            </aliases>
            <definition>unit of length used in earlier survey data in some countries, slightly different than the current international yard</definition>
        </unit>
        <unit>
            <def>5280 US_survey_feet</def>
            <aliases>
                <name> <singular>US_survey_mile</singular> </name>
                <name> <singular>US_statute_mile</singular> </name>
            </aliases>
            <definition>unit of length used for earlier survey data in some countries, slightly slightly different than the current international mile</definition>
        </unit>
        <unit>
            <def>16.5 US_survey_feet</def>
            <aliases>
                <name> <singular>rod</singular> </name>
                <name> <singular>pole</singular> </name>
                <name> <singular>perch</singular> </name>
            </aliases>
            <definition>unit of length equal to one-fourth of a surveyor's chain</definition>
        </unit>
        <unit>
            <def>660 US_survey_feet</def>
            <aliases> <name> <singular>furlong</singular> </name> </aliases>
            <definition>unit of length equal to 1/8 mile or 10 chains</definition>
        </unit>
        <unit>
            <def>6 US_survey_feet</def>
            <aliases> <name> <singular>fathom</singular> </name> </aliases>
            <definition>unit of length equal to 6 feet in the imperial and US customary systems, typically used for measuring depth of water</definition>
        </unit>
        <unit>
            <def>2.54 cm</def>
            <aliases>
                <name> <singular>international_inch</singular> </name>
                <name> <singular>inch</singular> </name>
                <symbol>in</symbol>
            </aliases>
            <definition>unit of length equal to 25.4 mm by definition, used in imperial and US customary systems</definition>
        </unit>
        <unit>
            <def>12 international_inches</def>
            <aliases>
                <name>
                    <singular>international_foot</singular>
                    <plural>international_feet</plural>
                </name>
                <name>
                    <singular>foot</singular>
                    <plural>feet</plural>
                </name>
                <symbol>ft</symbol>
            </aliases>
            <definition>unit of length equal to 12 international inches, in the imperial and US customary systems; primarily used in the United States</definition>
        </unit>
        <unit>
            <def>3 international_feet</def>
            <aliases>
                <name> <singular>international_yard</singular> </name>
                <name> <singular>yard</singular> </name>
                <symbol>yd</symbol>
            </aliases>
            <definition>unit of length equal to 3 international feet, in the imperial and US customary systems; primarily used in the United States</definition>
        </unit>
        <unit>
            <def>5280 international_feet</def>
            <aliases>
                <name> <singular>international_mile</singular> </name>
                <name> <singular>mile</singular> </name>
                <symbol>mi</symbol>
            </aliases>
            <definition>unit of length equal to 5280 feet, equal to 12 international inches, in the imperial and US customary systems; primarily used in the United States and other smaller countries with ties to the US or United Kingdom</definition>
        </unit>
        <unit>
            <def>inch/72</def>
            <aliases>
                <name> <singular>big_point</singular> </name>
            </aliases>
            <definition>unit of length equal to 1/72 inch, standardized unit in modern computer-based publishing for measuring font size and other small items on a printed page (contrast to printers_point)</definition>
        </unit>
        <unit>
            <def>inch/3</def>
            <aliases>
                <name> <singular>barleycorn</singular> </name>
            </aliases>
            <definition>unit of length based in medieval laws of England and Wales, defining an inch as being 3 barleycorns long (length of a corn of barley); still the basis for current shoe sizes in Great Britain and Ireland</definition>
        </unit>
        <unit>
            <def>191.835 foot</def>
            <aliases>
                <name> <singular>arpentlin</singular> </name>
            </aliases>
            <definition>unit of length in French regions; a linear arpent is of length 10 perch (10 rod)</definition>
        </unit>

    <!-- Angular Velocity -->
        <unit>
            <comment>exact</comment>
            <def>rotation/second</def>
            <aliases>
                <name>
                    <singular>rotation_per_second</singular>
                    <plural>rotations_per_second</plural>
                </name>
                <symbol>rps</symbol>
                <symbol>cps</symbol>
            </aliases>
            <definition>unit of angular velocity</definition>
        </unit>
        <unit>
            <comment>exact</comment>
            <def>rotation/minute</def>
            <aliases> <symbol>rpm</symbol> </aliases>
            <definition>unit of angular velocity measuring the angular distance covered by a rotating object, divided by the amount of time used to cover that distance; measured perpendicular to the plane of rotation, with direction usually indicated by the right-hand rule</definition>
        </unit>

    <!-- Lineic Mass -->
        <unit>
            <def>1.111111e-7 kg/m</def>
            <aliases>
                <name> <singular>denier</singular> </name>
            </aliases>
            <definition>unit of lineic mass density for fibers, equal to the mass in grams per 9000 meters (more common in United States and United Kingdom); a single strand of silk is approximately one denier</definition>
        </unit>
        <unit>
            <comment>exact</comment>
            <def>1e-6 kg/m</def>
            <aliases>
                <name> <singular>tex</singular> </name>
            </aliases>
            <definition>unit of lineic mass density for fibers, defined as mass in grams per 1000 meters (more common in Canada and Continental Europe)</definition>
        </unit>

    <!-- Mass per unit time (includes flow) -->
        <unit>
            <def>5.72135e-11 kg/(Pa.s.m^2)</def>
            <aliases>
                <name>
                    <singular>perm_0C</singular>
                    <plural>perms_0C</plural>
                </name>
            </aliases>
            <definition>unit of mass per unit time (includes flow) for how fast water vapor flows through substance, or permeance; equals 1 gram of water vapor per hour, per square meter, per millimeter of mercury at 0 degrees C</definition>
        </unit>
        <unit>
            <def>5.74525e-11 kg/(Pa.s.m^2)</def>
            <aliases>
                <name>
                    <singular>perm_23C</singular>
                    <plural>perms_23C</plural>
                </name>
            </aliases>
            <definition>unit of mass per unit time for how fast water vapor flows through substance, or permeance; equals 1 gram of water vapor per hour, per square meter, per millimeter of mercury at 23 degrees C</definition>
        </unit>

    <!-- Area -->
        <unit>
            <def>5.067075e-10 m^2</def>
            <aliases>
                <name> <singular>circular_mil</singular> </name>
            </aliases>
            <definition>unit of area equal to the area of a one-mil diameter circle</definition>
        </unit>
        <unit>
            <comment>porous solid permeability</comment>
            <def>9.869233e-13 m^2</def>
            <aliases> <name> <singular>darcy</singular> </name> </aliases>
            <definition>unit of area for measuring permeability to fluid, equal to 1 cubic centimeter of fluid with 1 centipoise viscosity in 1 second through a 1-square-centimeter cross section of porous medium 1 centimeter long at 1 atmosphere</definition>
        </unit>
        <unit>
            <comment>exact</comment>
            <def>160 rod^2</def>
            <aliases>
                <name> <singular>acre</singular> </name>
            </aliases>
            <definition>unit of area in the US Customary System, used in land and sea floor measurement, equal to 43560 square feet</definition>
        </unit>

    <!-- Volume -->
        <unit>
            <comment>An "acre.foot", however, is 1233.4867714897 m^3.  Odd.</comment>
            <def>1.233489e3 m^3</def>
            <aliases>
                <name>
                    <singular>acre_foot</singular>
                    <plural>acre_feet</plural>
                </name>
            </aliases>
            <definition>unit of volume used to describe large-scale water resources in the United State; equal to the volume of one acre of surface area with one foot of depth depth</definition>
        </unit>
        <unit>
            <def>2.359737e-3 m^3</def>
            <aliases>
                <name>
                    <singular>board_foot</singular>
                    <plural>board_feet</plural>
                </name>
            </aliases>
            <definition>unit of volume equal to the cubic contents of a piece of lumber one foot square and one inch thick, used in measuring logs and lumber in the United States and Canada</definition>
        </unit>
        <unit>
            <def>3.523907e-2 m^3</def>
            <aliases>
                <name> <singular>bushel</singular> </name>
                <symbol>bu</symbol>
            </aliases>
            <definition>unit of volume defined as 2150.42 cubic inches or 4 pecks in the US Customary system (and formerly in England), where it is used as a dry measure</definition>
        </unit>
        <unit>
            <comment>exact</comment>
            <def>bushel/4</def>
            <aliases>
                <name> <singular>peck</singular> </name>
                <symbol>pk</symbol>
            </aliases>
            <definition>unit of volume defined as 537.6 cubic inches  in the US Customary system (and formerly in England), where it is used as a dry measure</definition>
        </unit>
        <unit>
            <comment>exact</comment>
            <def>4.546090e-3 m^3</def>
            <aliases>
                <name> <singular>Canadian_liquid_gallon</singular> </name>
            </aliases>
            <definition>unit of volume for liquids in the Imperial system</definition>
        </unit>
        <unit>
            <def>4.404884e-3 m^3</def>
            <aliases>
                <name> <singular>US_dry_gallon</singular> </name>
            </aliases>
            <definition>unit of volume for dry measure in the US Customary system, defined as 1/2 peck or 1/8 bushel</definition>
        </unit>
        <unit>
            <comment>exact</comment>
            <def>cm^3</def>
            <aliases> <symbol>cc</symbol> </aliases>
            <definition>unit of volume equal to the volume of a cube 1 centimeter on each side</definition>
        </unit>
        <unit>
            <comment>exact</comment>
            <def>1 m^3</def>
            <aliases>
                <name> <singular>stere</singular> </name>
            </aliases>
            <definition>unit of volume equal to a cubic meter, originally defined primarily as a measure for firewood</definition>
        </unit>
        <unit>
            <def>2.831685 m^3</def>
            <aliases>
                <name> <singular>register_ton</singular> </name>
            </aliases>
            <definition>unit of volume used for internal capacity of ships, equal to 100 cubic feet</definition>
        </unit>
        <unit>
            <comment>exact</comment>
            <def>US_dry_gallon/4</def>
            <aliases>
                <name> <singular>US_dry_quart</singular> </name>
                <name> <singular>dry_quart</singular> </name>
            </aliases>
            <definition>unit of volume for dry measure in the US Customary system, equal to 1/32 US bushel</definition>
        </unit>
        <unit>
            <comment>exact</comment>
            <def>US_dry_gallon/8</def>
            <aliases>
                <name> <singular>US_dry_pint</singular> </name>
                <name> <singular>dry_pint</singular> </name>
            </aliases>
            <definition>unit of volume for dry measure in the US Customary system, equal to 1/2 US dry quart</definition>
        </unit>
        <unit>
            <def>3.785412e-3 m^3</def>
            <aliases>
                <name> <singular>US_liquid_gallon</singular> </name>
                <name> <singular>liquid_gallon</singular> </name>
                <name> <singular>gallon</singular> </name>
            </aliases>
            <definition>unit of volume for liquid measure in the US Customary system, defined as 3.785412 liters</definition>
        </unit>
        <unit>
            <comment>The following is the definition of the petroleum industry</comment>
            <def>42 US_liquid_gallon</def>
            <aliases>
                <name> <singular>barrel</singular> </name>
                <symbol>bbl</symbol>
            </aliases>
            <definition>unit of volume used by US and Canadian petroleum organizations</definition>
        </unit>
        <unit>
            <comment>The following is exact regardless of the definition of "barrel"</comment>
            <def>barrel/4</def>
            <aliases>
                <name> <singular>firkin</singular> </name>
            </aliases>
            <definition>unit of volume whose exact quantity depends on the type of barrel on which it is defined; in this table it is defined based on the oil barrel used by the petroleum industry</definition>
        </unit>
        <unit>
            <comment>exact</comment>
            <def>US_liquid_gallon/4</def>
            <aliases>
                <name> <singular>US_liquid_quart</singular> </name>
                <name> <singular>liquid_quart</singular> </name>
                <name> <singular>quart</singular> </name>
            </aliases>
            <definition>unit of volume for liquid measure in the US Customary system, equal to 1/4 liquid gallon</definition>
        </unit>
        <unit>
            <comment>exact</comment>
            <def>US_liquid_gallon/8</def>
            <aliases>
                <name> <singular>US_liquid_pint</singular> </name>
                <name> <singular>liquid_pint</singular> </name>
                <name> <singular>pint</singular> </name>
                <symbol>pt</symbol>
            </aliases>
            <definition>unit of volume for liquid measure in the US Customary system, equal to 1/8 liquid gallon</definition>
        </unit>
        <unit>
            <comment>exact</comment>
            <def>US_liquid_gallon/16</def>
            <aliases>
                <name> <singular>US_liquid_cup</singular> </name>
                <name> <singular>liquid_cup</singular> </name>
                <name> <singular>cup</singular> </name>
            </aliases>
            <definition>unit of volume for liquid measure in the US Customary system, equal to 1/16 liquid gallon</definition>
        </unit>
        <unit>
            <comment>exact</comment>
            <def>US_liquid_gallon/32</def>
            <aliases>
                <name> <singular>US_liquid_gill</singular> </name>
                <name> <singular>liquid_gill</singular> </name>
                <name> <singular>gill</singular> </name>
            </aliases>
            <definition>unit of volume for liquid measure in the US Customary system, equal to 1/32 liquid gallon</definition>
        </unit>
        <unit>
            <comment>exact</comment>
            <def>US_liquid_gallon/128</def>
            <aliases>
                <name> <singular>US_fluid_ounce</singular> </name>
                <name> <singular>US_liquid_ounce</singular> </name>
                <name> <singular>fluid_ounce</singular> </name>
                <name> <singular>liquid_ounce</singular> </name>
                <symbol>oz</symbol>
                <symbol>floz</symbol>
            </aliases>
            <definition>unit of volume for liquid measure in the US Customary system, equal to 1/128 liquid gallon</definition>
        </unit>
        <unit>
            <comment>exact</comment>
            <def>US_fluid_ounce/2</def>
            <aliases>
                <name> <singular>tablespoon</singular> </name>
                <symbol>Tbl</symbol>
                <symbol>Tbsp</symbol>
                <symbol>tbsp</symbol>
                <symbol>Tblsp</symbol>
                <symbol>tblsp</symbol>
            </aliases>
            <definition>unit of volume for liquid measure in the US Customary system, equal to 1/2 liquid ounce</definition>
        </unit>
        <unit>
            <comment>exact</comment>
            <def>US_fluid_ounce/8</def>
            <aliases>
                <name> <singular>fluid_dram</singular> </name>
                <symbol>fldr</symbol>
            </aliases>
            <definition>unit of volume for liquid measure in the apothecary system, equal to 1/8 liquid ounce</definition>
        </unit>
        <unit>
            <comment>exact</comment>
            <def>tablespoon/3</def>
            <aliases>
                <name> <singular>teaspoon</singular> </name>
                <symbol>tsp</symbol>
            </aliases>
            <definition>unit of volume defined as 1/3 tablespoon, the actual volume of which can vary depending on the measurement system (but is based on the US Customary system in this database)</definition>
        </unit>
        <unit>
            <comment>exact</comment>
            <def>4.546090e-3 m^3</def>
            <aliases>
                <name> <singular>UK_liquid_gallon</singular> </name>
            </aliases>
            <definition>unit of volume for liquid measure in the Imperial system</definition>
        </unit>
        <unit>
            <comment>exact</comment>
            <def>UK_liquid_gallon/4</def>
            <aliases>
                <name> <singular>UK_liquid_quart</singular> </name>
            </aliases>
            <definition>unit of volume for liquid measure in the Imperial system, equal to 1/4 liquid gallon</definition>
        </unit>
        <unit>
            <comment>exact</comment>
            <def>UK_liquid_gallon/8</def>
            <aliases>
                <name> <singular>UK_liquid_pint</singular> </name>
            </aliases>
            <definition>unit of volume for liquid measure in the Imperial system, equal to 1/8 liquid gallon</definition>
        </unit>
        <unit>
            <comment>exact</comment>
            <def>UK_liquid_gallon/16</def>
            <aliases>
                <name> <singular>UK_liquid_cup</singular> </name>
            </aliases>
            <definition>unit of volume for liquid measure in the Imperial system, equal to 1/16 liquid gallon</definition>
        </unit>
        <unit>
            <comment>exact</comment>
            <def>UK_liquid_gallon/32</def>
            <aliases>
                <name> <singular>UK_liquid_gill</singular> </name>
            </aliases>
            <definition>unit of volume for liquid measure in the Imperial system, equal to 1/32 liquid gallon</definition>
        </unit>
        <unit>
            <comment>exact</comment>
            <def>UK_liquid_gallon/160</def>
            <aliases>
                <name> <singular>UK_fluid_ounce</singular> </name>
                <name> <singular>UK_liquid_ounce</singular> </name>
            </aliases>
            <definition>unit of volume for liquid measure in the Imperial system, equal to 1/160 liquid gallon</definition>
        </unit>
        <unit>
            <def>lg(re (1e-6 m)^3)</def>
            <aliases> <symbol>BZ</symbol> </aliases>
            <definition>logarithmic unit used to compare the reflectivity (Z) of an unknown remote object, to the reflective return created by a droplet of rain with a diameter of 1 mm; is the base unit for "dBz", which is the typical logarithmic unit for measuring atmospheric radar reflectivity; a value of 0 Bz (0 DBz) corresponds to the return from a single cubic micron; a value of 6 Bz (60 DBz) corresponds to extremely heavy rain.</definition>
        </unit>

    <!-- Time -->
        <unit>
            <def>1e-8 s</def>
            <aliases> <name> <singular>shake</singular> </name> </aliases>
            <definition>unit of time approximating the lifetime of an individual neutron, useful for describing very brief durations, e.g., in nuclear physics</definition>
        </unit>
        <unit>
            <def>8.616409e4 s</def>
            <aliases>
                <name> <singular>sidereal_day</singular> </name>
            </aliases>
            <definition>unit of time that it takes the earth to complete one revolution with respect to a star, roughly 23 hours, 56 minutes, 4 seconds</definition>
        </unit>
        <unit>
            <def>3.590170e3 s</def>
            <aliases>
                <name> <singular>sidereal_hour</singular> </name>
            </aliases>
            <definition>unit of time equal to 1/24 sidereal day</definition>
        </unit>
        <unit>
            <def>5.983617e1 s</def>
            <aliases>
                <name> <singular>sidereal_minute</singular> </name>
            </aliases>
            <definition>unit of time equal to 1/60 sidereal hour</definition>
        </unit>
        <unit>
            <def>0.9972696 s</def>
            <aliases>
                <name> <singular>sidereal_second</singular> </name>
            </aliases>
            <definition>unit of time equal to 1/60 sidereal second</definition>
        </unit>
        <unit>
            <def>3.155815e7 s</def>
            <aliases>
                <name> <singular>sidereal_year</singular> </name>
            </aliases>
            <definition>unit of time for the earth to make one complete revolution around the sun, relative to the fixed stars</definition>
        </unit>
        <unit>
            <def>3.15569259747e7 s</def>
            <aliases>
                <name> <singular>tropical_year</singular> </name>
                <name> <singular>year</singular> </name>
                <!-- The following is commented-out because "a" already maps to "are"
                <symbol>a</symbol>
                -->
                <symbol>yr</symbol>
            </aliases>
            <definition>unit of time; Interval between 2 successive passages of sun through vernal equinox (365.242198781 days). See http://www.ast.cam.ac.uk/pubinfo/leaflets/, http://aa.usno.navy.mil/AA/, and http://adswww.colorado.edu/adswww/astro_coord.html</definition>
        </unit>
        <unit>
            <def>29.530589 day</def>
            <aliases>
                <name> <singular>lunar_month</singular> </name>
            </aliases>
            <definition>unit of time equal to the average time between successive new or full moons; equal to approximately 29 days, 12 hours, 44 minutes</definition>
        </unit>
        <unit>
            <def>365 day</def>
            <aliases>
                <name> <singular>common_year</singular> </name>
            </aliases>
            <definition>unit of time corresponding to a 'normal' calendar year, that is, one without insertion of a leap day</definition>
        </unit>
        <unit>
            <def>366 day</def>
            <aliases>
                <name> <singular>leap_year</singular> </name>
            </aliases>
            <definition>unit of time corresponding to a calendar year with a leap day inserted</definition>
        </unit>
        <unit>
            <def>365.25 day</def>
            <aliases>
                <name> <singular>Julian_year</singular> </name>
            </aliases>
            <definition>unit of time recognized by the International Astronomical Union for use in astronomy, defined as 365.25 days of 86400 seconds</definition>
        </unit>
        <unit>
            <def>365.2425 day</def>
            <aliases>
                <name> <singular>Gregorian_year</singular> </name>
            </aliases>
            <definition>unit of time based on the Gregorian Calendar, the one commonly used today; approximates the tropical year as 365 + 97/400 days</definition>
        </unit>
        <unit>
            <def>27.321661 day</def>
            <aliases>
                <name> <singular>sidereal_month</singular> </name>
            </aliases>
            <definition>unit of time based on 1/12 of the sidereal year</definition>
        </unit>
        <unit>
            <def>27.321582 day</def>
            <aliases>
                <name> <singular>tropical_month</singular> </name>
            </aliases>
            <definition>unit of time based on 1/12 of the tropical year</definition>
        </unit>
        <unit>
            <def>14 day</def>
            <aliases>
                <name> <singular>fortnight</singular> </name>
            </aliases>
            <definition>unit of time commonly defined as 14 days</definition>
        </unit>
        <unit>
            <def>7 day</def>
            <aliases> <name> <singular>week</singular> </name> </aliases>
            <definition>unit of time commonly defined as 7 days</definition>
        </unit>
        <unit>
            <comment>multiple values have been proposed for the amount of time represented by a 'jiffy'</comment>
            <def>0.01 s</def>
            <aliases> <name> <singular>jiffy</singular> </name> </aliases>
            <definition>unit of time used in computer animation as a method of defining playback rate</definition>
        </unit>
        <unit>
            <def>1e9 year</def>
            <aliases> <name> <singular>eon</singular> </name> </aliases>
            <definition>unit of time defined in astronomy as 1 billion years</definition>
        </unit>
        <unit>
            <def>year/12</def>
            <aliases> <name> <singular>month</singular> </name> </aliases>
            <definition>unit of time defined as the average length of time for a calendar month</definition>
        </unit>

    <!-- Volume per time -->
        <unit>
            <comment>exact</comment>
            <def>1e6 m^3/s</def>
            <aliases>
                <name> <singular>sverdrup</singular> </name>
                <!-- The following is commented-out because "Sv" means
                     "sievert" in the SI unit-system.
                <symbol>Sv</symbol>
                -->
            </aliases>
            <definition>unit of volume transport, used almost exclusively to measure the volumetric rate of ocean currents</definition>
        </unit>

    <!-- Acceleration -->
        <unit>
            <comment>exact</comment>
            <def>9.806650 m/s^2</def>
            <aliases>
                <name> <singular>standard_free_fall</singular> </name>
            </aliases>
            <definition>unit of acceleration corresponding to the nominal gravitational acceleration of an object in a vacuum near the surface of earth</definition>
        </unit>
        <unit>
            <comment>should be local</comment>
            <def>standard_free_fall</def>
            <aliases> <name> <singular>gravity</singular> </name> </aliases>
            <definition>unit of acceleration synonymous with standard rate of free fall (in earth's gravity)</definition>
        </unit>

    <!-- Some "units" that make subsequent definitions easier -->
        <unit>
            <comment>exact</comment>
            <def>gravity 1000 kg/m^3</def>
            <aliases>
                <name> <singular>conventional_water</singular> </name>
                <name> <singular>water</singular> </name>
                <symbol>H2O</symbol>
                <symbol>h2o</symbol>
            </aliases>
            <definition>specifies the acceleration at the earth's surface of a substance with the density of water</definition>
        </unit>
        <unit>
            <def>gravity 999.972 kg/m^3</def>
            <aliases>
                <name>
                    <singular>water_4C</singular>
                    <plural>waters_4C</plural>
                </name>
                <name>
                    <singular comment="actually 39.2 F">water_39F</singular>
                    <plural>waters_39F</plural>
                </name>
            </aliases>
            <definition>specifies the acceleration at the earth's surface of a substance with the density of water at 4 degrees C</definition>
        </unit>
        <unit>
            <def>gravity 999.001 kg/m^3</def>
            <aliases>
                <name>
                    <singular>water_60F</singular>
                    <plural>waters_60F</plural>
                </name>
            </aliases>
            <definition>specifies the acceleration at the earth's surface of a substance with the density of water at 60 degrees F</definition>
        </unit>
        <unit>
            <def>gravity 13595.10 kg/m^3</def>
            <aliases>
                <name>
                    <singular>mercury_0C</singular>
                    <plural>mercuries_0C</plural>
                </name>
                <name>
                    <singular>mercury_32F</singular>
                    <plural>mercuries_32F</plural>
                </name>
                <name>
                    <singular>conventional_mercury</singular>
                    <plural>conventional_mercuries</plural>
                </name>
                <symbol>Hg</symbol>
            </aliases>
            <definition>specifies the acceleration at the earth's surface of a substance with the density of mercury at 0 degrees C</definition>
        </unit>
        <unit>
            <def>gravity 13556.8 kg/m^3</def>
            <aliases>
                <name>
                    <singular>mercury_60F</singular>
                    <plural>mercuries_60F</plural>
                </name>
            </aliases>
            <definition>specifies the acceleration at the earth's surface of a substance with the density of mercury at 60 degrees F</definition>
        </unit>

    <!-- Force -->
        <unit>
            <def>standard_free_fall</def>
            <aliases> <name> <singular>force</singular> </name> </aliases>
            <definition>unit of force equivalent to the force generated by the effect of gravity</definition>
        </unit>
        <unit>
            <comment>exact</comment>
            <def>1e-5 N</def>
            <aliases> <name> <singular>dyne</singular> </name> </aliases>
            <definition>unit of force, equal to the force that produces an acceleration of one centimeter per second per second on a mass of one gram (the standard centimeter-gram-second unit of force)</definition>
        </unit>
        <unit>
            <comment>exact</comment>
            <def>9.806650e-3 N</def>
            <aliases> <name> <singular>pond</singular> </name> </aliases>
            <definition>unit of force, equal to the magnitude of the force exerted by one gram of mass in a 9.80665 m/s2 gravitational field</definition>
        </unit>
        <unit>
            <comment>exact</comment>
            <def>9.806650 N</def>
            <aliases>
                <name> <singular>force_kilogram</singular> </name>
                <name>
                    <singular>kilogram_force</singular>
                    <plural>kilograms_force</plural>
                </name>
                <symbol>kgf</symbol>
            </aliases>
            <definition>unit of force, equal to the magnitude of the force exerted by one kilogram of mass in a 9.80665 m/s2 gravitational field</definition>
        </unit>
        <unit>
            <comment>exact</comment>
            <def>2.780139e-1 N</def>
            <aliases>
                <name> <singular>force_ounce</singular> </name>
                <name>
                    <singular>ounce_force</singular>
                    <plural>ounces_force</plural>
                </name>
                <symbol>ozf</symbol>
            </aliases>
            <definition>unit of force, equal to the magnitude of the force exerted by one ounce of mass in a 9.80665 m/s2 gravitational field</definition>
        </unit>
        <unit>
            <comment>exact</comment>
            <def>4.4482216152605 N</def>
            <aliases>
                <name> <singular>force_pound</singular> </name>
                <name>
                    <singular>pound_force</singular>
                    <plural>pounds_force</plural>
                </name>
                <symbol>lbf</symbol>
            </aliases>
            <definition>unit of force, equal to the magnitude of the force exerted by one pound of mass in a 9.80665 m/s2 gravitational field</definition>
        </unit>
        <unit>
            <comment>exact</comment>
            <def>1.382550e-1 N</def>
            <aliases>
                <name> <singular>poundal</singular> </name>
            </aliases>
            <definition>unit of force, that which is necessary to accelerate 1 pound-mass to 1 foot per second per second</definition>
        </unit>
        <unit>
            <comment>exact</comment>
            <def>gram force</def>
            <aliases>
                <name>
                    <singular>gram_force</singular>
                    <plural>grams_force</plural>
                </name>
                <name>
                    <singular>force_gram</singular>
                </name>
                <symbol>gf</symbol>
            </aliases>
            <definition>unit of force, equal to the magnitude of the force exerted by one gram of mass in a 9.80665 m/s2 gravitational field</definition>
        </unit>
        <unit>
            <comment>exact</comment>
            <def>2000 force_pound</def>
            <aliases>
                <name> <singular>force_ton</singular> </name>
                <name>
                    <singular>ton_force</singular>
                    <plural>tons_force</plural>
                </name>
            </aliases>
            <definition>unit of force, equal to the magnitude of the force exerted by one ton of mass in a 9.80665 m/s2 gravitational field (specifically a short ton of mass)</definition>
        </unit>
        <unit>
            <comment>exact</comment>
            <def>1000 lbf</def>
            <aliases> <name><singular>kip</singular></name> </aliases>
            <definition>unit of force, equal to the magnitude of the force exerted by one thousand pounds of mass in a 9.80665 m/s2 gravitational field</definition>
        </unit>

    <!-- Pressure, Stress -->
        <unit>
            <comment>exact</comment>
            <def>1.01325e5 Pa</def>
            <aliases>
                <name> <singular>standard_atmosphere</singular> </name>
                <name> <singular>atmosphere</singular> </name>
                <symbol>atm</symbol>
            </aliases>
            <definition>unit of pressure, an international reference pressure intended to represent the mean atmospheric pressure at mean sea level at the latitude of Paris, France</definition>
        </unit>
        <unit>
            <comment>exact; note that the symbol 'at' clashes with that of the katal ('kat'), the SI unit of catalytic activity</comment>
            <def>1 kg gravity/cm2</def>
            <aliases>
                <name> <singular>technical_atmosphere</singular> </name>
                <symbol>at</symbol>
            </aliases>
            <definition>unit of pressure equal to one kilogram force per square centimeter</definition>
        </unit>
        <unit>
            <def>cm H2O</def>
            <aliases>
                <symbol>cm_H2O</symbol>
                <symbol>cmH2O</symbol>
            </aliases>
            <definition>unit of pressure derived from pressure head calculations using metrology; represents the pressure exerted by a column of water of 1 cm height at 4 degrees C</definition>
        </unit>
        <unit>
            <comment>exact</comment>
            <def>inch water_39F</def>
            <aliases>
                <name>
                    <singular>inch_H2O_39F</singular>
                    <plural>inches_H2O_39F</plural>
                </name>
            </aliases>
            <definition>unit of pressure representing the pressure exerted by a column of water of 1 inch height at 39 degrees F</definition>
        </unit>
        <unit>
            <comment>exact</comment>
            <def>inch water_60F</def>
            <aliases>
                <name>
                    <singular>inch_H2O_60F</singular>
                    <plural>inches_H2O_60F</plural>
                </name>
            </aliases>
            <definition>unit of pressure representing the pressure exerted by a column of water of 1 inch height at 60 degrees F</definition>
        </unit>
        <unit>
            <def>foot water</def>
            <aliases>
                <name>
                    <singular>foot_water</singular>
                    <plural>feet_water</plural>
                </name>
                <name>
                    <singular>foot_H2O</singular>
                    <plural>feet_H2O</plural>
                </name>
                <name>
                    <singular>footH2O</singular>
                    <plural>feetH2O</plural>
                </name>
                <symbol>ftH2O</symbol>
                <symbol>fth2o</symbol>
            </aliases>
            <definition>unit of pressure representing the pressure exerted by a column of water of 1 foot height at 4 degrees C</definition>
        </unit>
        <unit>
            <def>cm Hg</def>
            <aliases>
                <symbol>cm_Hg</symbol>
                <symbol>cmHg</symbol>
            </aliases>
            <definition>unit of pressure representing the pressure exerted by a column of mercury of 1 cm height at 0 degrees C</definition>
        </unit>
        <unit>
            <comment>exact</comment>
            <def>mm mercury_0C</def>
            <aliases>
                <name>
                    <singular>millimeter_Hg_0C</singular>
                    <plural>millimeters_Hg_0C</plural>
                </name>
            </aliases>
            <definition>unit of pressure representing the pressure exerted by a column of mercury of 1 mm height at 0 degrees C</definition>
        </unit>
        <unit>
            <comment>exact</comment>
            <def>inch mercury_32F</def>
            <aliases>
                <name>
                    <singular>inch_Hg_32F</singular>
                    <plural>inches_Hg_32F</plural>
                </name>
            </aliases>
            <definition>unit of pressure representing the pressure exerted by a column of mercury of 1 inch height at 32 degrees F</definition>
        </unit>
        <unit>
            <comment>exact</comment>
            <def>inch mercury_60F</def>
            <aliases>
                <name>
                    <singular>inch_Hg_60F</singular>
                    <plural>inches_Hg_60F</plural>
                </name>
            </aliases>
            <definition>unit of pressure representing the pressure exerted by a column of mercury of 1 inch height at 60 degrees F</definition>
        </unit>
        <unit>
            <def>mm Hg</def>
            <aliases>
                <name>
                    <singular>millimeter_Hg</singular>
                    <plural>millimeters_Hg</plural>
                </name>
                <name> <singular>torr</singular> </name>
                <symbol>mm_Hg</symbol>
                <symbol>mm_hg</symbol>
                <symbol>mmHg</symbol>
                <symbol>mmhg</symbol>
            </aliases>
            <definition>unit of pressure representing the pressure exerted by a column of mercury of 1 mm height at 0 degrees C; approximately (within 0.000015%, generally below measurement error) 1 Torr, which is 1/760 standard atmospheric pressure</definition>
        </unit>
        <unit>
            <def>inch Hg</def>
            <aliases>
                <name>
                    <singular>inch_Hg</singular>
                    <plural>inches_Hg</plural>
                </name>
                <symbol>in_Hg</symbol>
                <symbol>inHg</symbol>
            </aliases>
            <definition>unit of pressure representing the pressure exerted by a column of mercury of 1 inch height at 0 degrees C</definition>
        </unit>
        <unit>
            <comment>exact</comment>
            <def>1 pound gravity/in^2</def>
            <aliases> <symbol>psi</symbol> </aliases>
            <definition>unit of pressure representing the pressure exerted, due to gravity, by a one-pound mass, of area one square inch; commonly referred to as "pounds per square inch"</definition>
        </unit>
        <unit>
            <comment>exact</comment>
            <def>kip/in^2</def>
            <aliases> <symbol>ksi</symbol> </aliases>
            <definition>unit of pressure representing the pressure exerted, due to gravity, by a 1000-pound mass, of area one square inch</definition>
        </unit>
        <unit>
            <comment>exact</comment>
            <def>0.1 N/m^2</def>
            <aliases>
                <name> <singular>barie</singular> </name>
                <name> <singular>barye</singular> </name>
            </aliases>
            <definition>unit of pressure equal to one dyne per square centimeter</definition>
        </unit>
        <unit>
            <comment>sound pressure level</comment>
            <def>lg(re 20e-6 Pa)</def>
            <aliases> <symbol>B_SPL</symbol> </aliases>
            <definition>logarithmic unit used to compare the sound pressure of an unknown sound to a standard reference sound pressure; is the base unit for "dB_SPL", a more typical logarithmic unit for measuring sound pressure (the SI unit for sound pressure is pascal); the standard reference sound pressure in air or other gases is 20 microPascal, which is usually considered the threshold of human hearing (at 1 kHz)</definition>
        </unit>

    <!-- Viscosity -->
        <unit>
            <comment>exact</comment>
            <def>1e-1 Pa.s</def>
            <aliases>
                <name> <singular>poise</singular> </name>
            </aliases>
            <definition>unit of dynamic viscosity, corresponding to 0.1 pascal-second (pascal-second: a fluid placed between two plates, when one plate is pushed sideways with a shear stress of one pascal, moves a distance equal to the thickness of the layer between the plates in one second)</definition>
        </unit>
        <unit>
            <comment>exact</comment>
            <def>1e-4 m^2/s</def>
            <aliases>
                <name> <singular>stokes</singular> </name>
                <symbol>St</symbol>
            </aliases>
            <definition>unit of kinematic viscosity, measuring the ratio of the dynamic viscosity to the density of the fluid; water at 20 degrees C has a kinematic viscosity about 100 stokes, or more cmomonly, 1 cSt</definition>
        </unit>
        <unit>
            <comment>exact</comment>
            <def>10/(Pa.s)</def>
            <aliases> <name> <singular>rhe</singular> </name> </aliases>
            <definition>unit of fluidity (reciprocal of velocity), measured in reciprocal poise</definition>
        </unit>

    <!-- Energy, Work, Quantity of Heat -->
        <unit>
            <comment>exact</comment>
            <def>1e-7 J</def>
            <aliases> <name> <singular>erg</singular> </name> </aliases>
            <definition>unit of work, equal to the amount of work done by a force of one dyne exerted for a distance of one centimeter (in CGS base units, one gram centimeter-squared per second-squared)</definition>
        </unit>
        <unit>
            <comment>exact</comment>
            <def>1.05505585262e3 J</def>
            <aliases>
                <name>
                    <singular>IT_Btu</singular>
                    <plural>IT_Btus</plural>
                </name>
                <name>
                    <singular>Btu</singular>
                    <plural>Btus</plural>
                </name>
            </aliases>
            <definition>unit of energy, equal to the energy needed to cool or heat one pound of water by one degree F; this uses the International Steam Table (IT) calorie , defined by the Fifth International Conference on the properties of Steam (1956)</definition>
        </unit>
        <unit>
            <comment>exact (reference NIST Guide to SI Units)</comment>
            <def>1.05506e8 J</def>
            <aliases>
                <name> <singular>EC_therm</singular> </name>
            </aliases>
            <definition>unit of energy legally defined by the Council Directive of 20 December 1979, Council of the European Communities (now the European Union, EU);.roughly equal to 100,000 IT_Btu </definition>
        </unit>
        <unit>
            <comment>exact</comment>
            <def>4.184000 J</def>
            <aliases>
                <name> <singular>thermochemical_calorie</singular> </name>
            </aliases>
            <definition>unit of heat energy defined as 4.184 Joules exactly (International Standard ISO 31-4: Quantities and units, Part 4: Heat); approximately the energy needed to increase the temperature of 1 gram of water by 1 C</definition>
        </unit>
        <unit>
            <comment>exact</comment>
            <def>4.1868 J</def>
            <aliases>
                <name> <singular>IT_calorie</singular> </name>
                <name> <singular>calorie</singular> </name>
                <symbol>cal</symbol>
            </aliases>
            <definition>unit of heat energy used in thermochemistry, the International Steam Table (IT) calorie defined by the Fifth International Conference on the properties of Steam (1956)</definition>
        </unit>
        <unit>
            <comment>by definition</comment>
            <def>4.184 MJ/kg</def>
            <aliases>
                <name> <singular>TNT</singular><noplural/></name>
            </aliases>
            <definition>unit of energy; approximately the energy released by the detonation of a given amount of mass of TNT</definition>
        </unit>
        <unit>
            <comment>by definition</comment>
            <def>4.184e9 J</def>
            <aliases>
                <name>
                    <singular>ton_TNT</singular>
                    <plural>tons_TNT</plural>
                </name>
            </aliases>
            <definition>unit of energy; approximately the energy released by the detonation of a 1000 kilograms of TNT</definition>
        </unit>
        <unit>
            <comment>exact</comment>
            <def>1.054804e8 J</def>
            <aliases>
                <name> <singular>US_therm</singular> </name>
                <name> <singular>therm</singular> </name>
                <symbol>thm</symbol>
            </aliases>
            <definition>unit of energy legally defined in the U.S. Federal Register of July 27, 1968, and the legal unit used by the U.S. natural gas industry</definition>
        </unit>
        <unit>
            <comment>exact</comment>
            <def>watt.hour</def>
            <aliases>
                <name> <singular>watthour</singular> </name>
            </aliases>
            <definition>unit of energy equal to the product of the power in watts and the time in hours (if the energy is being transmitted or used at a constant rate (power) over a period of time); one watt is equal to 1 Joule/second</definition>
        </unit>
        <unit>
            <comment>exact</comment>
            <def>1e9 eV</def>
            <aliases> <symbol>bev</symbol> </aliases>
            <definition>unit of energy corresponding to 1 billion electron volts (eV)</definition>
        </unit>

    <!-- Power, Radiant Flux -->
        <unit>
            <comment>exact</comment>
            <def>V.A</def>
            <aliases>
                <name> <singular>voltampere</singular> </name>
                <symbol>VA</symbol>
            </aliases>
            <definition>unit of electric power equal to the product of one volt and one ampere, equivalent to one watt for direct current systems and a unit of apparent power for alternating current systems</definition>
        </unit>
        <unit>
            <def>9.80950e3 W</def>
            <aliases>
                <name> <singular>boiler_horsepower</singular> </name>
            </aliases>
            <definition>unit of power equal to the power required to evaporate 34.5 lb of fresh water at 212 degrees F in one hour; describes a boiler's capacity to deliver steam to a steam engine</definition>
        </unit>
        <unit>
            <comment>shaft_horsepower is a unit of power as delivered by a drive shaft at its output (e.g., of a ship, aircraft engine, or helicopter rotor; typically not automobiles due to drive train losses)</comment>
            <def>7.456999e2 W</def>
            <aliases>
                <name> <singular>shaft_horsepower</singular> </name>
                <name> <singular>horsepower</singular> </name>
                <symbol>hp</symbol>
            </aliases>
            <definition>unit of power originally corresponding to the estimated typical power of draft horses, calculated as lifting 33000 pounds one foot in one minute (550 foot-pounds/second)</definition>
        </unit>
        <unit>
            <def>7.35499e2 W</def>
            <aliases>
                <name> <singular>metric_horsepower</singular> </name>
            </aliases>
            <definition>unit of power corresponding to a calculation of 75 kilogram-meters/second</definition>
        </unit>
        <unit>
            <comment>exact</comment>
            <def>7.460000e2 W</def>
            <aliases>
                <name> <singular>electric_horsepower</singular> </name>
            </aliases>
            <definition>unit of power defined in the International System of Units as exactly 746 W; generally used for power used by electrical machines</definition>
        </unit>
        <unit>
            <def>7.46043e2 W</def>
            <aliases>
                <name> <singular>water_horsepower</singular> </name>
            </aliases>
            <definition>unit of power used in the U.S. primarily in rating pumps; calculated as pump capacity Q (gallons per minute) times pump pressure ("head") of P (feet of head), divided by 3956 water horsepower; the calculation assumes water density is 8 1/3 pounds per U.S. gallon, which is not exact.</definition>
        </unit>
        <unit>
            <def>7.4570e2 W</def>
            <aliases>
                <name> <singular>UK_horsepower</singular> </name>
            </aliases>
            <definition>unit of power originally corresponding to the estimated typical power of draft horses, calculated as lifting 33000 pounds one foot in one minute (550 foot-pounds/second), as calculated/specified in the United Kingdom</definition>
        </unit>
        <unit>
            <def>12000 Btu/hr</def>
            <aliases>
                <name> <singular>refrigeration_ton</singular> </name>
                <name>
                    <singular>ton_of_refrigeration</singular>
                    <plural>tons_of_refrigeration</plural>
                </name>
            </aliases>
            <definition>unit of power describing the heat-extraction capacity of cooling equipment; defined as the heat absorbed by melting 1 short ton of pure ice at 0 degrees C in 24 hours</definition>
        </unit>
        <unit>
            <def>lg(re 1 W)</def>
            <aliases> <symbol>BW</symbol> </aliases>
            <definition>unit of power in decibel scale, referenced to 1 watt; the power in bel-watts is equal to 100 times the base 10 logarithm of the power in watts (making decibel-watt, the more common term, 10 times the base 10 log of the power in watts)</definition>
        </unit>
        <unit>
            <def>lg(re 1 mW)</def>
            <aliases> <symbol>Bm</symbol> </aliases>
            <definition>unit of power in decibel scale, referenced to 1 milliwatt; the power in bel-milliwatts is equal to 100 times the base 10 logarithm of the power in milliwatts (making decibel-milliwatt, the more common term, 10 times the base 10 log of the power in watts)</definition>
        </unit>

    <!-- Heat -->
        <unit>
            <def>1.55e-1 K.m^2/W</def>
            <aliases> <name> <singular>clo</singular> </name> </aliases>
            <definition>unit of thermal resistance used in describing the insulating value of clothing; the amount of thermal resistance needed to maintain in comfort a resting subject in a normally ventilated room (air movement 10 cm/sec) at a temperature of 20 degrees C and a humidity less than 50%</definition>
        </unit>

    <!-- Electricity and Magnetism -->
        <unit>
            <def>10 A</def>
            <aliases> <name><singular>abampere</singular></name> </aliases>
            <definition>basic unit of electricity in the electromagnetic CGS system of units</definition>
        </unit>
        <unit>
            <def>7.957747e-1 A</def>
            <aliases> <name><singular>gilbert</singular></name> </aliases>
            <definition>unit of electricity/magnetism</definition>
        </unit>
        <unit>
            <def>3.335640e-10 A</def>
            <aliases>
                <name><singular>statampere</singular></name>
            </aliases>
            <definition>unit of electricity/magnetism</definition>
        </unit>
        <unit>
            <def>10 A</def>
            <aliases> <name><singular>biot</singular></name> </aliases>
            <definition>basic unit of electricity in the electromagnetic CGS system of units (same as abampere), named after Jean-Baptiste Biot</definition>
        </unit>
        <unit>
            <comment>exact</comment>
            <def>1e9 F</def>
            <aliases> <name> <singular>abfarad</singular> </name> </aliases>
            <definition>unit of electricity/magnetism</definition>
        </unit>
        <unit>
            <comment>exact</comment>
            <def>1e-9 H</def>
            <aliases>
                <name> <singular>abhenry</singular> </name>
            </aliases>
            <definition>unit of electricity/magnetism</definition>
        </unit>
        <unit>
            <comment>exact</comment>
            <def>1e9 S</def>
            <aliases> <name> <singular>abmho</singular> </name> </aliases>
            <definition>unit of electricity/magnetism</definition>
        </unit>
        <unit>
            <comment>exact</comment>
            <def>1e-9 ohm</def>
            <aliases> <name> <singular>abohm</singular> </name> </aliases>
            <definition>unit of electricity/magnetism</definition>
        </unit>
        <unit>
            <comment>exact</comment>
            <def>1e-8 V</def>
            <aliases> <name> <singular>abvolt</singular> </name> </aliases>
            <definition>unit of electricity/magnetism</definition>
        </unit>
        <unit>
            <def>1.602176487e-19 C</def>
            <aliases> <symbol>e</symbol> </aliases>
            <definition>unit of electricity/magnetism</definition>
        </unit>
        <unit>
            <def>9.64957e4 C</def>
            <aliases>
                <name> <singular>chemical_faraday</singular> </name>
            </aliases>
            <definition>unit of electricity/magnetism</definition>
        </unit>
        <unit>
            <def>9.65219e4 C</def>
            <aliases>
                <name> <singular>physical_faraday</singular> </name>
            </aliases>
            <definition>unit of electricity/magnetism</definition>
        </unit>
        <unit>
            <def>9.648531e4 C</def>
            <aliases>
                <name> <singular>C12_faraday</singular> </name>
                <name> <singular>faraday</singular> </name>
            </aliases>
            <definition>unit of electricity/magnetism</definition>
        </unit>
        <unit>
            <comment>exact</comment>
            <def>1e-9 T</def>
            <aliases>
                <name> <singular>gamma</singular> </name>
            </aliases>
            <definition>unit of electricity/magnetism</definition>
        </unit>
        <unit>
            <comment>exact</comment>
            <def>1e-4 T</def>
            <aliases>
                <name> <singular>gauss</singular> </name>
            </aliases>
            <definition>unit of electricity/magnetism</definition>
        </unit>
        <unit>
            <comment>exact</comment>
            <def>1e-8 Wb</def>
            <aliases>
                <name> <singular>maxwell</singular> </name>
            </aliases>
            <definition>unit of electricity/magnetism</definition>
        </unit>
        <unit>
            <def>7.957747e1 A/m</def>
            <aliases>
                <name> <singular>oersted</singular> </name>
                <symbol>Oe</symbol>
            </aliases>
            <definition>unit of electricity/magnetism</definition>
        </unit>
        <unit>
            <def>3.335640e-10 C</def>
            <aliases>
                <name> <singular>statcoulomb</singular> </name>
            </aliases>
            <definition>unit of electricity/magnetism</definition>
        </unit>
        <unit>
            <def>1.112650e-12 F</def>
            <aliases>
                <name> <singular>statfarad</singular> </name>
            </aliases>
            <definition>unit of electricity/magnetism</definition>
        </unit>
        <unit>
            <def>8.987554e11 H</def>
            <aliases>
                <name> <singular>stathenry</singular> </name>
            </aliases>
            <definition>unit of electricity/magnetism</definition>
        </unit>
        <unit>
            <def>1.112650e-12 S</def>
            <aliases>
                <name> <singular>statmho</singular> </name>
            </aliases>
            <definition>unit of electricity/magnetism</definition>
        </unit>
        <unit>
            <def>8.987554e11 ohm</def>
            <aliases>
                <name> <singular>statohm</singular> </name>
            </aliases>
            <definition>unit of electricity/magnetism</definition>
        </unit>
        <unit>
            <def>2.997925e2 V</def>
            <aliases>
                <name> <singular>statvolt</singular> </name>
            </aliases>
            <definition>unit of electricity/magnetism</definition>
        </unit>
        <unit>
            <def>1.256637e-7 Wb</def>
            <aliases>
                <name> <singular>unit_pole</singular> </name>
            </aliases>
            <definition>unit of electricity/magnetism</definition>
        </unit>
        <unit>
            <def>lg(re 1 V)</def>
            <aliases> <symbol>BV</symbol> </aliases>
            <definition>unit of electricity/magnetism</definition>
        </unit>
        <unit>
            <comment>rms voltage</comment>
            <def>lg(re 0.775 V)</def>
            <aliases> <symbol>Bv</symbol> </aliases>
            <definition>unit of electricity/magnetism</definition>
        </unit>
        <unit>
            <def>lg(re 1e-6 V)</def>
            <aliases> 
                <symbol comment="uses MICRO SIGN">B&#xB5;V</symbol>
            </aliases>
            <definition>unit of electricity/magnetism</definition>
        </unit>

    <!-- Thermodynamic Temperature -->
        <unit>
            <def>K/1.8</def>
            <aliases>
                <symbol comment="DEGREE SIGN">&#xB0;R</symbol>    
                <name>
                    <singular>degree_rankine</singular>
                    <plural>degrees_rankine</plural>
                </name>
                <name>
                    <singular>degreeR</singular>
                    <plural>degreesR</plural>
                </name>
                <name>
                    <singular>degree_R</singular>
                    <plural>degrees_R</plural>
                </name>
                <name>
                    <singular>degR</singular>
                    <plural>degsR</plural>
                </name>
                <name>
                    <singular>deg_R</singular>
                    <plural>degs_R</plural>
                </name>
            </aliases>
            <definition>unit of thermodynamic temperature</definition>
        </unit>
        <unit>
            <def>&#xB0;R @ 459.67</def>
            <aliases>
                <symbol comment="DEGREE SIGN">&#xB0;F</symbol>    
                <symbol comment="DEGREE FAHRENHEIT">&#x2109;</symbol>   
                <name> <singular>fahrenheit</singular> </name>
                <name>
                    <singular>degree_fahrenheit</singular>
                    <plural>degrees_fahrenheit</plural>
                </name>
                <name>
                    <singular>degreeF</singular>
                    <plural>degreesF</plural>
                </name>
                <name>
                    <singular>degree_F</singular>
                    <plural>degrees_F</plural>
                </name>
                <name>
                    <singular>degF</singular>
                    <plural>degsF</plural>
                </name>
                <name>
                    <singular>deg_F</singular>
                    <plural>degs_F</plural>
                </name>
            </aliases>
            <definition>unit of thermodynamic temperature</definition>
        </unit>

    <!-- Illumination -->
        <unit>
            <def>1.076391e-1 lx</def>
            <aliases>
                <name> <singular>footcandle</singular> </name>
            </aliases>
            <definition>unit of illumination</definition>
        </unit>
        <unit>
            <comment>exact</comment>
            <def>3.426259 cd/m^2</def>
            <aliases>
                <name> <singular>footlambert</singular> </name>
            </aliases>
            <definition>unit of illumination</definition>
        </unit>
        <unit>
            <comment>exact</comment>
            <def>(1e4/pi) cd/m^2</def>
            <aliases>
                <name> <singular>lambert</singular> </name>
            </aliases>
            <definition>unit of illumination</definition>
        </unit>
        <unit>
            <comment>exact</comment>
            <def>1e4 cd/m^2</def>
            <aliases>
                <name> <singular>stilb</singular> </name>
                <symbol>sb</symbol>
            </aliases>
            <definition>unit of illumination</definition>
        </unit>
        <unit>
            <comment>exact</comment>
            <def>1e4 lm/m^2</def>
            <aliases>
                <name> <singular>phot</singular> </name>
                <symbol>ph</symbol>
            </aliases>
            <definition>unit of illumination</definition>
        </unit>
        <unit>
            <comment>exact</comment>
            <def>1 cd/m^2</def>
            <aliases>
                <name> <singular>nit</singular> </name>
                <symbol>nt</symbol>
            </aliases>
            <definition>unit of illumination</definition>
        </unit>
        <unit>
            <comment>exact</comment>
            <def>4.184000e4 J/m^2</def>
            <aliases>
                <name> <singular>langley</singular> </name>
            </aliases>
            <definition>unit of illumination</definition>
        </unit>
        <unit>
            <comment>exact</comment>
            <def>cd/(pi m^2)</def>
            <aliases>
                <name> <singular>blondel</singular> </name>
                <name> <singular>apostilb</singular> </name>
            </aliases>
            <definition>unit of illumination</definition>
        </unit>

    <!-- Miscellaneous -->
        <unit>
            <comment>exact</comment>
            <def>100/m</def>
            <aliases> <name> <singular>kayser</singular> </name> </aliases>
            <definition></definition>
        </unit>
        <unit>
            <comment>exact</comment>
            <def>gravity</def>
            <aliases>
                <name> <singular>geopotential</singular> </name>
                <name> <singular>dynamic</singular> </name>
                <symbol>gp</symbol>
            </aliases>
            <definition></definition>
        </unit>
        <unit>
            <comment>exact</comment>
            <def>2056 hours</def>
            <aliases>
                <name> <singular>work_year</singular> </name>
            </aliases>
            <definition></definition>
        </unit>
        <unit>
            <comment>exact</comment>
            <def>work_year/12</def>
            <aliases>
                <name> <singular>work_month</singular> </name>
            </aliases>
            <definition></definition>
        </unit>
        <unit>
            <comment>exact</comment>
            <def>1e-6 m^2 s^-1 K kg^-1</def>
            <aliases>
                <name> <singular>potential_vorticity_unit</singular> </name>
                <symbol>PVU</symbol>
            </aliases>
            <definition></definition>
        </unit>
        <unit>
            <def>1</def>
            <aliases>
                <name> <singular>count</singular> </name>
            </aliases>
            <definition></definition>
        </unit>
        <unit>
            <def>1</def>
            <aliases>
                <name> <singular>bit</singular> </name>
            </aliases>
            <definition></definition>
        </unit>
        <unit>
            <def>8</def>
            <aliases>
                <name><singular>octet</singular></name>
                <name><singular>byte</singular></name>
            </aliases>
            <definition></definition>
        </unit>
        <unit>
            <def>446.2 micromoles/meter^2</def>
            <aliases>
                <name> <singular>dobson</singular> </name>
                <symbol>DU</symbol>
            </aliases>
            <definition></definition>
        </unit>
        <unit>
            <def>1/avogadro_constant</def>
            <name><singular>molecule</singular></name>
            <aliases>
                <name><singular>molec</singular></name>
                <name><singular>nucleon</singular></name>
                <name><singular>nuc</singular></name>
            </aliases>
            <definition></definition>
        </unit>
</unit-system>