multi-word expression

Noun

 * 1)  A lexeme-like unit made up of a sequence of two or more words that has properties that are not predictable from the properties of the individual words or their normal mode of combination, such as an idiom ("pay the piper"), a phrasal noun ("steam iron"), a phrasal preposition ("in front of"), or a phrasal verb ("buy off").

Usage notes

 * Often abbreviated as MWE.