i·den·ti·fi·er / īˈdentəˌfīər/ • n. a person or thing that identifies something: the new number is to be known as the “unique patient identifier.” ∎  Comput. a sequence of characters used to identify or refer to a program or an element, such as a variable or a set of data, within it.

identifier A string of characters used to identify (or name) some element of a program. The kind of element that may be named depends on the programming language; it may be a variable, a data structure, a procedure, a statement, a higher-level unit, or the program itself.