metalanguage

from WordNet (r) 3.0 (2006)

metalanguage
    n 1: a language that can be used to describe languages

from The Collaborative International Dictionary of English v.0.48

metalanguage \metalanguage\ n.
   Any language that can be used to describe another language or
   system of symbols.
   [WordNet 1.5]

from The Free On-line Dictionary of Computing (8 July 2008)

metalanguage

   1. [theorem proving] A language in which proofs are
   manipulated and tactics are programmed, as opposed to the
   logic itself (the "{object language}").  The first {ML} was
   the metalanguage for the Edinburgh {LCF} proof assistant.

   2. [logic] A language in which to discuss the truth of
   statements in another language.