VII vs heptad

VII and heptad both are nouns.

Word	Noun	Adjective	Verb	Adverb
VII	Yes	No	No	No
heptad	Yes	No	No	No

As nouns, VII and heptad are synonyms defined as:

Other synonyms of VII include 7, septenary, septet, seven, sevener.

VII (noun)	heptad (noun)
the cardinal number that is the sum of six and one	the cardinal number that is the sum of six and one