Noun

(identities)

Sameness, identicalness; the quality or fact of (several specified things) being the same.

* 1997 , Hydrothermal Vent Fauna'', in ''Advances in Marine Biology: The Biogeography of the Oceans , page 111:

The difference or character that marks off an individual from the rest of the same kind, selfhood.

*

A name or persona—the mask or appearance one presents to the world—by which one is known.

This criminal has taken on several identities .

Sense of who one is.

I've been through so many changes, I have no sense of identity .

This nation has a strong identity .

(algebra, computing) Any function which maps all elements of its domain to themselves.

(algebra) An element of an algebraic structure which, when applied to another element under an operation in that structure, yields this, second element.

Noun

(en noun)

Someone who identifies; a person who establishes the identity of.

* {{quote-book, year=2001, title=The Career Guide to the Horse Industry, author=Theodore A. Landers

, passage=The Identifier personally inspects each horse in each race by verifying the lip tattoo, body color, head and leg markings, scars, and chestnut (night eyes). citation

* {{quote-book, year=2004, title=Great Horse Racing Mysteries: True Tales from the Track, author=John McEvoy

, passage=The foal papers are documents recording the horse's registration; no horse can start in any race unless his papers are in the hands of the track's identifier . citation

Something that identifies or uniquely points to something or someone else.

* {{quote-book, year=2008, author=Ted Dunstone, Neil Yager, title=Biometric System and Data Analysis

, passage=Prehistoric artists used hand-prints in cave paintings, perhaps as as 'signature'. They might be considered the earliest example of a biometric identifier .}}

A guidebook that helps determine the specific class of an object (such as a mushroom, herb, fish, bird, drug, or mineral), or its individual identity (such as that of a star).

(programming, operating systems) A formal name used in source code to refer to a variable, function, procedure, package, etc. or in an operating system to refer to a process, user, group, etc.

(databases) A primary key.