identification

Identification fields single an object out from its context or from among other objects, and thereby indicate exactly what is referred to when that object is dealt with.

A name, address, or reference key can distinguish the object being described. These identifiers answer which object is meant, while its measurements and qualities describe that object.

Coordinates locate a point, and an identifier distinguishes an entity within a reference system. Different forms of identification can refer to the same object without expressing the same kind of information.