Token

From Wikipedia, the free encyclopedia

Token may refer to:

• Token (railway signalling), a physical object given to a locomotive driver to authorize him to use a particular stretch of single railway track
• Token coin, a piece of metal or other composition used as a substitute for currency; includes subway tokens
• Tokenism, the inclusion of a single person (or very few people) of a group so an organization can publicly claim to be inclusive
• Token character, a supporting character in a story who has no real relevance to the plot but is included to conform to expected standards, such as featuring ethnic minorities in a cast of a predominantly other ethnicity.
• Knight's token, carried by a medieval knight
• In philosophy, computational linguistics, and information retrieval, a token is an instance of a type; see Type-token distinction

[edit] Popular culture

• Token Black, the only African American child in the South Park television series.
• The Tokens, a band perhaps best known for their hit "The Lion Sleeps Tonight".

[edit] Computing

There are two classes of meaning of 'token' in computing:

• An object which represents the (often exclusive) right to perform some operation:
  • Token (Petri Net), an object used in Petri net theory
  • Session token, a unique identifier which is generated and sent from a server to a software client to identify an interaction session and which the client usually stores as an HTTP cookie
  • Security token (also known as a hardware token, authentication token or cryptographic token), a physical device that an authorized user of computer services is given to aid in authentication
  • Access token, a system object representing the subject of access control operations
  • Token ring, a local area network technology in which a virtual object known as a token is passed between devices on the network, authorizing them to communicate
  • Invitation tokens, sometimes called "codes", sometimes used as a method of curbing website registration for a number of purposes.

• An atomic object in parsing:
  • Token (parser), usually a word or other atomic parse element
  • Tokenizing, the operation of splitting a string of characters into a set of tokens in lexical analysis

[edit] Sport

• Token (Racing team), a Formula One team run by Ron Dennis.