Token - Definition and Overview

Token can mean one of several things:

• In lexical analysis, a token is an atomic element within a string. To tokenize is to replace systematically some more complex string by such a token.
• A token may also be a piece of metal or other composition item used as a substitute for currency; see also exonumia or casino token.
• In business or politics, a token can be a single person of a disadvantaged group hired very publicly so the organization can claim to be inclusive or representative. In South Park, Token Williams is the only black child on the show.
• On railways, a token is a physical object given to a locomotive driver to authorize him to use a particular stretch of single track.
• In computing, a token is a virtual object that is passed between computers or other devices on a network and similarly authorizes them to communicate. Only the device with the token may communicate, to avoid clashing with other devices.
• In the Windows NT family of operating systems, a token is a system object representing the subject of access control operations.