Some words or phrases have 'special' meaning beyond the combination of constituent parts.
- 'White House' is the white house where the US president lives.
- 'black board' is where you draw on with chalk at school [actually more recently a green board and in the past 20 years a 'white board' (which is white)].
Negative examples (phrases or constructions that are not examples of the concept):
- 'quasi-' anything: (I find) is -not- a 'special thing' for me, it is not a new word with a meaning all its own, 'quasi' is just a productive modifier that doesn't mean anything more than itself and the new word it makes can be judged simply as 'almost like an X'
- colors usually (with some example exceptions above) don't make anything 'new' - a 'red door' is just a door colored red. If it took on some cultural connection, then it might need an additional dictionary specification for that term 'red door'.
I'm not talking about the figurative (non-literal, metaphorical) uses of such terms, but certainly metaphor ("White House' as the seat of American government), and idiom ('raining cats and dogs') are examples of the idea 'a set phrase'. When a neologism or coinage becomes an accepted item.
For example, if you look at a list of words that begin with the prefix 'quasi-', almost entirely, these words are not special or used ever again, or if they're used again it is simply out of logical need of the construction. They don't describe a recognizably repeatable 'thing'.
What I'm looking for is the appropriate way to designate a locution that is more than the sum of its parts.
I've been using the bland term 'set phrase' to call this phenomenon. It itself is not particularly evocative of the 'noncompositional' aspect of some phrases.
Is set phrase the best way to name this phenomenon? or is there another?