VIII vs octonary

VIII and octonary both are nouns.

Word	Noun	Adjective	Verb	Adverb
VIII	Yes	No	No	No
octonary	Yes	No	No	No

As nouns, VIII and octonary are synonyms defined as:

Other synonyms of VIII include 8, eight, eighter, eighter from Decatur, octad, octet, ogdoad.

VIII (noun)	octonary (noun)
the cardinal number that is the sum of seven and one	the cardinal number that is the sum of seven and one