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• In mathematics, the term identity, in distinction to an equation, refers to a equational statement that always holds. Most commonly identities in this sense are used in universal algebra to define a certain class of structures. In another popular usage, an identity is considered as a mathematical entity that does not change other objects. In this spirit, one talks about identity functions, identity elements, identity matrices, identity relations, and identity morphisms.
• In philosophy, identity has both metaphysical and logical uses.
• Digital identity refers to the representation of identity in terms of digital information. A digital identity can be understood as the set of digital information that is attributable to any given entity. This entity may be human (an individual or a community), a physical object, or even digital information itself.
• In object-oriented programming, identity (object-oriented programming) describes a property of objects that allows those objects to be distinguished from each other.
• In the social sciences, identity has specific meanings, stemming from cognitive theory, sociology, politics, and psychology. See identity (social science).
• For security systems, authentication identity refers to the characteristics that a person has that can be verified.
• In philosophy of mind the identity theory of mind holds that the mind is identical to the brain.
• In music, identity (music) is used in a similar sense as the universal algebra above.
• For the periodical publication "Identity", see Identity (magazine) .
• Identity is also a movie starring John Cusack.
• Identity may be short for identity document