identityyoudaoicibaDictYouDict[identity 词源字典]
identity: [16] The historical meaning of identity is best preserved in its derivative identical [17] – ‘the same’. For its ultimate source was Latin idem ‘same’, a pronoun (formed from id ‘it, that one’ with the suffix -dem) used in English since the 17th century for referring to a previously cited author or text. This formed the basis of late Latin identitās, which meant literally ‘sameness’; the main meaning of its English descendant identity, ‘individuality, set of definitive characteristics’, arose from the notion of something always being the same or always being itself (rather than something else).
[identity etymology, identity origin, 英语词源]
identity (n.)youdaoicibaDictYouDict
c. 1600, "sameness, oneness," from Middle French identité (14c.), from Late Latin (5c.) identitatem (nominative identitas) "sameness," from ident-, comb. form of Latin idem (neuter) "the same" (see identical); abstracted from identidem "over and over," from phrase idem et idem. [For discussion of Latin formation, see entry in OED.] Earlier form of the word in English was idemptitie (1560s), from Medieval Latin idemptitas. Term identity crisis first recorded 1954. Identity theft attested from 1995.