A card or badge showing the official identity of the bearer.

plural of identical twin

One of exactly two siblings produced from the splitting of a single zygote.

(psychiatry) A mental disorder characterized by the presence of two or more personality states or distinct identities that repeatedly take control of a person's behavior.

(philosophy) The principle that, if two objects are indistinguishable from one another with respect to all of their properties, then they are identical.

plural of identity card

(psychology) A person's internal sense of self as belonging to a particular gender or genders, or to no gender.

A condition in which the patient experiences significant gender dysphoria: the diagnostic classification most commonly applied to transgender/transsexual people.

plural of standard of identity

(US, Canada, law) A government regulation establishing the criteria which must be met before a product may be labeled as being a certain food.