Identifier
An
identifier is a name that identifies (that is, labels the identity of) either a unique object or a unique
class of objects, where the "object" or class may be an idea, physical object (or class thereof), or physical substance (or class thereof). The abbreviation
ID often refers to identity, identification (the process of identifying), or an identifier (that is, an instance of identification). An identifier may be a word, number, letter, symbol, or any combination of those. The words, numbers, letters, or symbols may follow an encoding system (wherein letters, digits, words, or symbols
stand for (represent) ideas or longer names) or they may simply be arbitrary. When an identifier follows an encoding system, it is often referred to as a
code or
ID code. Identifiers that do not follow any encoding scheme are often said to be
arbitrary IDs; they are arbitrarily assigned and have no greater meaning. (Sometimes identifiers are called "codes" even when they are actually arbitrary, whether because the speaker believes that they have deeper meaning or simply because he is speaking casually and imprecisely.