Definition - A language or code that is used to discuss or describe another language.

Example -
Formal syntactic models, such as Chomsky's generative grammar, that are used to describe natural languages like English are metalanguages.

Etymology -
The term derives from the Greek meta, above or over + language.

Oxford English Dictionary -
Its first (English) citation is from 1936:
"The concepts analytic and contradictory in the language L, for instance, cannot be defined in L, as Carnap has shown. In order to escape from these restrictions one must build up a new language (a so-called meta-language) disposing of more means of expressing thoughts than the former."
(Mind XLV. 486)

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