enigma canon vs riddle canon

enigma canon and riddle canon both are nouns.

Word	Noun	Adjective	Verb	Adverb
enigma canon	Yes	No	No	No
riddle canon	Yes	No	No	No

As nouns, enigma canon and riddle canon are synonyms defined as:

enigma canon and riddle canon: a canon in which the entrances of successive parts were indicated by cryptic symbols and devices (popular in the 15th and 16th centuries)

Other synonyms of enigma canon include enigmatic canon, enigmatical canon.

enigma canon (noun)	riddle canon (noun)
a canon in which the entrances of successive parts were indicated by cryptic symbols and devices (popular in the 15th and 16th centuries)	a canon in which the entrances of successive parts were indicated by cryptic symbols and devices (popular in the 15th and 16th centuries)