A name or persona—the mask or appearance one presents to the world—by which one is known.
Sense of who one is.
(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.
Something that identifies or uniquely points to something or someone else.
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) 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.
(HTML) A code that distinguishes a particular element from all other elements in a document.