terce vs canonical hour

terce and canonical hour both are nouns.

Word	Noun	Adjective	Verb	Adverb
terce	Yes	No	No	No
canonical hour	Yes	No	No	No

As nouns, canonical hour is a hypernym of terce; that is, canonical hour is a word with a broader meaning than terce:

terce: the third canonical hour; about 9 a.m.
canonical hour: (Roman Catholic Church) one of seven specified times for prayer

terce (noun)	canonical hour (noun)
the third canonical hour; about 9 a.m.	(Roman Catholic Church) one of seven specified times for prayer