i·den·ti·ty – /aɪˈdɛntɪti, ɪˈdɛn-/ plural identities – the condition of being oneself or itself, and not another: He doubted his own identity. – condition or character as to who a person or what a thing is: a case of mistaken identity. – the state or fact of being the same one as described. – the sense of self, providing sameness and continuity in personality over time and sometimes disturbed in mental illnesses, as schizophrenia. – exact likeness in nature or qualities: an identity of interests. – an equation that is valid for all values of its variables.