Definition Of Meta

meta <philosophy> /me't*/ or /may't*/ or (Commonwealth) /mee't*/ A prefix meaning one level of description higher. If X is some concept then meta-X is data about, or processes operating on, X.

A metasyntactic variable [] (e.g. FOO) is a variable in notation used to describe syntax, and MetaLanguage is a language used to describe language (e.g. BNF).

For example, a metasyntax is syntax for specifying syntax, metalanguage is a language used to discuss language, meta-data is data about data, and meta-reasoning is reasoning about reasoning.

MetaData is "data about data." IE: Data that the system uses to determine how other data is processed.

This is difficult to explain briefly, but much hacker humour turns on deliberate confusion between meta-levels.

(The above is primarily from FOLDOC, the FreeOnLineDictionaryOfComputing at
Some more down to earth examples: Hmm, writing this it looks to me, that this is rather the format "meta-X is X about X", not "meta-X is data about X". Either these are two readings of "meta" or the data must have a special quality or the candidates for X must be data.


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