keystone vs anchor

keystone and anchor both are nouns.

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

As nouns, keystone and anchor are synonyms defined as:

Other synonyms of keystone include backbone, linchpin, lynchpin, mainstay.

keystone (noun)	anchor (noun)
the central building block at the top of an arch or vault	a mechanical device that prevents a vessel from moving
a central cohesive source of support and stability	a central cohesive source of support and stability
	a television reporter who coordinates a broadcast to which several correspondents contribute

keystone (verb)	anchor (verb)
	secure a vessel with an anchor
	fix firmly and stably