Definition: The set of all possible symbols in an application. For instance, input characters used by a finite state machine, letters making up strings in a language, or symbols in a pattern element. In some cases, an alphabet may be infinite.

See also don't care.

Note: An alphabet may be as simple as the booleans 1 and 0, or as rich as the key words and token types in a programming language.

Author: PEB

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Entry modified 17 December 2004.
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Cite this as:
Paul E. Black, "alphabet", in Dictionary of Algorithms and Data Structures [online], Paul E. Black, ed. 17 December 2004. (accessed TODAY) Available from: