Words with different meaning than root words [duplicate]

The are phrases whose meaning is not what you would get from combining its constituent words (i.e., they violate the Principle of compositionality).

1. Some are entity names, e.g.,
   • "weird science" is (usually) a movie, not a kind of science,
   • "grand theft auto" is a specific kind of felony or a computer game, not stealing a big car
2. Others are idioms, e.g.,
   • "kick a bucket" or
   • "pull a leg" or
   • "break a leg"
3. something else which escapes my mind at the moment...

What is the general term for this?

"Non-compositional phrase"?

The only other thing which comes to mind is mass-defective phrase :-)

Solution 1:

What you describe is referred to as a multiword expression (MWE) - one definition of which is idiosyncratic interpretations that cross word boundaries (or spaces). A fuller description (too detailed to be sensibly reproduced) can be found here.

Examples include: kick the bucket, throw to the lions.

Solution 2:

At least in Natural Language Processing, yes, this is frequently referred to as a "non-compositional phrase", or occasionally "non-compositional expression", "non-compositional idiom" or "non-compositional compound".

A couple examples:

• Dekang Lin's paper "Automatic Identification of Non-compositional Phrases" http://www.aclweb.org/anthology-new/P/P99/P99-1041.pdf

• Google's Patent for "Identifying non-compositional compounds" http://www.google.com/patents/US8572081

Solution 3:

The answer is 'idiom'.

This is the original meaning of the term, from French idiome, via late Latin from Greek idioma. (Oxford Dictionary of English; not OED). 'A group of words established by usage as having a meaning not deducible from those of the individual words.'