Definition -
(1) A structural linguistics' term for the branch of linguistics that studies the relationship of language to setting and cultural context.
(2) The study of metalanguages, i.e. languages that are used to discuss or describe other languages.

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

Oxford English Dictionary -
The first citation for the term in sense (2) is from 1974:
"Some linguists use the term metalinguistics in reference to the study of metalanguages, languages or codes used to discuss or describe other languages."
(Encycl. Brit. Micropædia VI. 827/3)

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