noun, plural i·den·ti·ties.
- the state or fact of remaining the same one or ones, as under varying aspects or conditions: The identity of the fingerprints on the gun with those on file provided evidence that he was the killer.
- the condition of being oneself or itself, and not another: He began to doubt his own identity.
- condition or character as to who a person or what a thing is; the qualities, beliefs, etc., that distinguish or identify a person or thing: a case of mistaken identity; a male gender identity; immigrants with strong ethnic identities.
- the state or fact of being the same one as described.
- the sense of self, providing sameness and continuity in personality over time and sometimes disturbed in mental illnesses, as schizophrenia.
- exact likeness in nature or qualities: an identity of interests.
- an instance or point of sameness or likeness: to mistake resemblances for identities.
- Logic. an assertion that two terms refer to the same thing.
- Mathematics.
- an equation that is valid for all values of its variables.
- Also called identity element, unit element, unity.an element in a set such that the element operating on any other element of the set leaves the second element unchanged.
- the property of a function or map such that each element is mapped into itself.
- the function or map itself.
- Australian Informal. an interesting, famous, or eccentric resident, usually of long standing in a community.
noun plural -ties
- the state of having unique identifying characteristics held by no other person or thing
- the individual characteristics by which a person or thing is recognized
- Also called: numerical identity the property of being one and the same individualhis loss of memory did not affect his identity
- Also called: qualitative identity the state of being the same in nature, quality, etcthey were linked by the identity of their tastes
- the state of being the same as a person or thing described or claimedthe identity of the stolen goods has not yet been established
- identification of oneself asmoving to London destroyed his Welsh identity
- logic
- that relation that holds only between any entity and itself
- an assertion that that relation holds, as Cicero is Tully
- maths
- an equation that is valid for all values of its variables, as in (x – y)(x + y) = x ² – y ². Often denoted by the symbol ≡
- Also called: identity elementa member of a set that when operating on another member, x, produces that member x: the identity for multiplication of numbers is 1 since x .1 = 1. x = xSee also inverse (def. 2b)
- Australian and NZ informal a well-known person, esp in a specified locality; figure (esp in the phrase an old identity)
n.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. n.
- The set of behavioral or personal characteristics by which an individual is recognizable as a member of a group.
- The distinct personality of an individual regarded as a persisting entity; individuality.