coherency vs continuity

coherency and continuity both are nouns.

Word	Noun	Adjective	Verb	Adverb
coherency	Yes	No	No	No
continuity	Yes	No	No	No

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

Other hyponyms of coherency include consistency.

coherency (noun)	continuity (noun)
logical and orderly and consistent relation of parts	the property of a continuous and connected period of time
the state of cohering or sticking together	a detailed script used in making a film in order to avoid discontinuities from shot to shot
	uninterrupted connection or union