IDENTIFIER
identifier
(noun) a symbol that establishes the identity of the one bearing it
Source: WordNet® 3.1
Etymology
Noun
identifier (plural identifiers)
Someone who identifies; a person who establishes the identity of.
Something that identifies or uniquely points to something or someone else.
A guidebook that helps determine the specific class of an object (such as a mushroom, herb, fish, bird, drug, or mineral), or its individual identity (such as that of a star).
(programming, operating systems) A formal name used in source code to refer to a variable, function, procedure, package, etc. or in an operating system to refer to a process, user, group, etc.
(HTML) A code that distinguishes a particular element from all other elements in a document.
(databases) A primary key.
Source: Wiktionary