boyyoudaoicibaDictYouDict[boy 词源字典]
boy: [13] The etymology of boy has long been problematical, but the now most generally accepted view is that it is probably a reduced form of an unrecorded Anglo-Norman *abuie or *embuie ‘fettered’, from the Old French verb embuier ‘fetter’. This came from Vulgar Latin *imboiāre, a compound verb based on Latin boiae ‘leather collar, fetter’, which was adapted from Greek boeiai doraí ‘ox-hides’ (hence ‘oxleather thongs’), from bous ‘ox’ (related to English bovine and cow).

The apparently implausible semantic connection is elucidated by the early meaning of boy in English, which was ‘male servant’; according to this view, a boy was etymologically someone kept in leather fetters, and hence a ‘slave’ or ‘servant’. The current main sense, ‘young male’, developed in the 14th century.

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boy (n.)youdaoicibaDictYouDict
mid-13c., boie "servant, commoner, knave, boy," of unknown origin. Possibly from Old French embuie "one fettered," from Vulgar Latin *imboiare, from Latin boia "leg iron, yoke, leather collar," from Greek boeiai dorai "ox hides." (Words for "boy" double as "servant, attendant" across the Indo-European map -- compare Italian ragazzo, French garçon, Greek pais, Middle English knave, Old Church Slavonic otroku -- and often it is difficult to say which meaning came first.)

But it also appears to be identical with East Frisian boi "young gentleman," and perhaps with Dutch boef "knave," from Middle Dutch boeve, perhaps from Middle Low German buobe. This suggests a gradational relationship to babe. For a different conjecture:
In Old English, only the proper name Boia has been recorded. ME boi meant 'churl, servant' and (rarely) 'devil.' In texts, the meaning 'male child' does not antedate 1400. ModE boy looks like a semantic blend of an onomatopoeic word for an evil spirit (*boi) and a baby word for 'brother' (*bo). [Liberman]



A noticable number of the modern words for 'boy', 'girl', and 'child' were originally colloquial nicknames, derogatory or whimsical, in part endearing, and finally commonplace. These, as is natural, are of the most diverse, and in part obscure, origin. [Buck]
Used slightingly of young men in Middle English; meaning "male negro slave or Asian personal servant of any age" attested from c. 1600. Exclamation oh, boy attested from 1892.