A name or persona—the mask or appearance one presents to the world—by which one is known.
Sense of who one is.
(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.
Esimerkit
[...] suggesting the two are different stages of the same species. The identity of the two species is further suggested by allozyme analysis [...]
This criminal has taken on several identities.
I've been through so many changes, I have no sense of identity.