Name for pairs of words with a strong association? [duplicate]

Certain words you hear in English are only ever heard in a single context. For example, skirl is used to describe the sound a bagpipe makes. Etymonline generously says the word is "rarely" heard outside that context, but I can't recall ever hearing it used for anything else. I imagine one could use it figuratively to describe another godawful high-pitched screech (sorry, bagpipe lovers), but there's no other bona fide usage for it.

What I want to know is stated in the title of the question: Is there a term for these one-off words? I'm sure there must be, but I can't think of what it might be.

Edit: Judging from some of the head-scratching comments I've received, there seems to be some confusion. Perhaps I did not make my meaning clear. I'm not looking for a word to describe the single instance of skirl. I'm asking about a class of words like skirl. I know there exist other examples of words that are only ever used in one context, but I can't think of any others at the moment.

It's a "stormy petrel." The idea, as described on the linked page, is that (for example) you never (or, at least, rarely) find a petrel that's not stormy. Similarly, "all shrift is short," and lots of other examples. One of the ones there is in fact "every skirl is of bagpipes."

Closely related are fossil words, which have no meaning outside of a certain set phrase. "Bated" survives only in "bated breath", for example.