Identifier

Name that identifies a unique entity

An identifier is a name that identifies either a unique object or a unique class of objects, where the "object" or class may be an idea, person, physical countable object, or physical noncountable substance. The abbreviation ID often refers to identity, identification, or an identifier. An identifier may be a word, number, letter, symbol, or any combination of those.

This keyword could refer to multiple things. Here are some suggestions: