dozenyoudaoicibaDictYouDict[dozen 词源字典]
dozen: [13] Dozen traces its ancestry back to the Latin word for ‘twelve’, duodecim. This was a compound formed from duo ‘two’ and decem ‘ten’. This gradually developed in the postclassical period via *dōdece to *doze, which, with the addition of the suffix -ēna, produced Old French dozeine, source of the English word.
=> duodenum[dozen etymology, dozen origin, 英语词源]
dozen (n.)youdaoicibaDictYouDict
c. 1300, from Old French dozaine "a dozen," from doze (12c.) "twelve," from Latin duodecim "twelve," from duo "two" + decem "ten" (see ten).

The Old French fem. suffix -aine is characteristically added to cardinals to form collectives in a precise sense ("exactly 12," not "about 12"). The dozens "invective contest" (1928) originated in slave culture, the custom probably African, the word probably from bulldoze (q.v.) in its original sense of "a whipping, a thrashing."