keystone vs coigne

keystone and coigne both are nouns.

Word	Noun	Adjective	Verb	Adverb
keystone	Yes	No	No	No
coigne	Yes	No	No	No

As nouns, coigne is a hyponym of keystone; that is, coigne is a word with a more specific, narrower meaning than keystone:

Other hyponyms of keystone include coign, quoin.

keystone (noun)	coigne (noun)
the central building block at the top of an arch or vault	the keystone of an arch
a central cohesive source of support and stability	expandable metal or wooden wedge used by printers to lock up a form within a chase