c. 1600, "sameness, oneness, state of being the same," from French identité (14c.), from Medieval Latin identitatem (nominative identitas) "sameness," ultimately from Latin idem (neuter) "the same" (see 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. Identity politics is attested by 1987.
"[I]dentity politics" [is] a phrase with notably wide currency in gay and lesbian communities. In common usage, the term identity politics refers to the tendency to base one's politics on a sense of personal identity—as gay, as Jewish, as Black, as female ..... [Diana Fuss, "Essentially Speaking," 1989]
1640s, "regard as the same," from French identifier, from identité (see identity). Sense of "determine the identity of, recognize as or prove to be the same" first recorded 1769. Meaning "make one (with), associate (oneself), regard oneself as being the essence of" is from 1780. Sense of "serve as means of identification" is attested by 1886. Related: Identified; identifying.
"personal identity, individuality, selfhood," 1650s, from Latin ipse "self" + -ity.
1640s, "treating of a thing as the same as another; act of making or proving to be the same," from French identification, probably from identifier (see identify). Psychological sense of "becoming or feeling oneself one with another" is from 1857. Meaning "act or process of determining the identity of something" is from 1859. Meaning "object or document which marks identity" is from 1947 (short for identification tag, card, etc.).
1610s as a term in logic; general sense of "being the same or very similar" is from 1630s, from Medieval Latin identicus "the same," from Late Latin identitas "identity, sameness," ultimately from combining form of Latin idem "the same" (see idem). Replaced Middle English idemptical (late 15c.), from Medieval Latin idemptitas "identity," from Latin idem. Related: Identically.
early 15c., occultacioun, "disguise or concealment of identity," from Latin occultationem (nominative occultatio), noun of action from past-participle stem of occultare "to hide, conceal," frequentative of occulere "to cover over, conceal" (see occult).
computerese word, 1948, coined by U.S. computer pioneer John W. Tukey, an abbreviation of binary digit, probably chosen for its identity with bit (n.1).
in La Raza, literally "the race," 1964, from American Spanish (see race (n.2)), "designating the strong sense of racial and cultural identity held by Mexican-Americans" [OED].