from The American Heritage® Dictionary of the English Language, 5th Edition.

  • noun The condition of being a certain person or thing.
  • noun The set of characteristics by which a person or thing is definitively recognizable or known.
  • noun The awareness that an individual or group has of being a distinct, persisting entity.
  • noun The fact or condition of being the same as something else.
  • noun The fact or condition of being associated or affiliated with something else.
  • noun Information, such as an identification number, used to establish or prove a person's individuality, as in providing access to a credit account.
  • noun An equation that is satisfied by any number that replaces the letter for which the equation is defined.
  • noun Identity element.

from The Century Dictionary.

  • noun The state of being the same; absolute sameness; that relation which anything bears to itself; loosely, essential or practical sameness. Properly, identity belongs only to the individual, thing, being, event, etc.
  • noun In mathematics: The relation of an expression to another symbol for itself: often denoted by three short parallel horizontal lines, ≡ (derived from the mark of equality, =).
  • noun In algebra: A relation of equivalence dependent only upon the very nature of the operations involved, and not at all upon the particular numbers operated with: for example, the identity of ab with ba.
  • noun An identical equation; an equation for any letter in which any number whatsoever may be substituted without destroying the equality or restricting the values of any other letter: for example, (a + b) + c = a + (b + c).

from the GNU version of the Collaborative International Dictionary of English.

  • noun The state or quality of being identical, or the same; sameness.
  • noun The condition of being the same with something described or asserted, or of possessing a character claimed.
  • noun (Math.) An identical equation.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

  • noun The sameness some individuals share to make up the same kind or universal.
  • noun The difference or character that marks off an individual from the rest of the same kind, selfhood.
  • noun A name or persona—the mask or appearance one presents to the world—by which one is known.
  • noun Knowledge of who one is.
  • noun algebra, computing Any function which maps all elements of its domain to themselves.
  • noun algebra An element of an algebraic structure which, when applied to another element under an operation in that structure, yields this, second element.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

  • noun the individual characteristics by which a thing or person is recognized or known
  • noun the distinct personality of an individual regarded as a persisting entity
  • noun exact sameness
  • noun an operator that leaves unchanged the element on which it operates


from The American Heritage® Dictionary of the English Language, 4th Edition

[French identité, from Old French identite, from Late Latin identitās, from Latin idem, the same (influenced by Late Latin essentitās, being, and identidem, repeatedly), from id, it; see i- in Indo-European roots.]

from Wiktionary, Creative Commons Attribution/Share-Alike License

Learned borrowing from Vulgar Latin identitas ("sameness"), from Latin idem ("the same"). See identical and idem.


Help support Wordnik (and make this page ad-free) by adopting the word identity.


  • In this sense, then, a thing's essence may be said to constitute its identity, when one uses the word ˜identity™ in this distinctive manner to speak of

    Ontological Dependence

  • E.G. create table table1 (id int identity (1,1) not null, name nvarchar (64)) go insert into table1 ( 'Hello world') go select @@identity


  • 1998, "Criteria of identity and the ˜identity mystic™", Erkenntnis, 48: 281-301.


  • The notion of transworld identity ” ˜identity across possible worlds™ ” is the notion that the same object exists in more than one possible world (with the actual world treated as one of the possible worlds).

    Transworld Identity

  • But often the shift in identity is purely for pleasure.

    First Person Plural

  • But often the shift in identity is purely for pleasure.

    First Person Plural

  • CAFFERTY: The term identity crisis has taken on a whole new meaning in this high tech age and that's because identity theft is a huge problem with very big consequences.

    CNN Transcript Apr 16, 2005

  • "A lot of people use the term identity management loosely," says John Lyons,


  • "A lot of people use the term identity management loosely," says John Lyons,


  • The lack of stylistic focus might hurt the label identity in a way, but my tastes are all over the map, and I think the label should reflect that to an extent.

    Side-Line news feed


Log in or sign up to get involved in the conversation. It's quick and easy.