(algebra) An element of an algebraic structure which when applied, in either order, to any other element via a binary operation yields the other element.

The act or process of idealizing. / The representation of natural objects, scenes, etc., in such a way as to show their most important characteristics; the study of the ideal.

(not comparable) Bearing full likeness by having precisely the same set of characteristics; indistinguishable.

(usually pluralized, chiefly philosophy) Something which has exactly the same properties as something else. / An identical twin.

A mandatory unique alphanumeric code (usually 17 characters long) assigned to each vehicle produced, stamped into the metal on the dashboard on the left-hand side (viewable through the windshield), and on the engine block and at least one other place somewhere on the body of the vehicle.

A picture of a person, reconstructed from strips showing facial features selected to match witnesses' descriptions; used by the police to build a likeness of a person sought for a crime.

(informal, chiefly derogatory) Indistinguishable from each other; mass-produced or mass-marketed.

In a civilian aircraft: a transponder that responds by sending a code identifying itself.

The deliberate assumption of another person's identity, usually to gain access to that person's finances or to frame a person for a crime.

A city in Georgia, United States. / An unincorporated community in Illinois. / An unincorporated community in South Dakota.