canonical vs canon

canonical is not a noun while canon is a noun.

Word	Noun	Adjective	Verb	Adverb
canonical	No	Yes	No	No
canon	Yes	No	No	No

canonical (noun)	canon (noun)
	a rule or especially body of rules or principles generally established as valid and fundamental in a field of art or philosophy
	a contrapuntal piece of music in which a melody in one part is imitated exactly in other parts
	a collection of books accepted as holy scripture especially the books of the Bible recognized by any Christian church as genuine and inspired
	a complete list of saints that have been recognized by the Roman Catholic Church
	a ravine formed by a river in an area with little rainfall
	a priest who is a member of a cathedral chapter

canonical (adjective)	canon (adjective)
of or relating to or required by canon law
appearing in a biblical canon
conforming to orthodox or recognized rules
reduced to the simplest and most significant form possible without loss of generality