VI vs hexad

VI and hexad both are nouns.

Word	Noun	Adjective	Verb	Adverb
VI	Yes	No	No	No
hexad	Yes	No	No	No

As nouns, VI and hexad are synonyms defined as:

Other synonyms of VI include 6, Captain Hicks, half a dozen, sestet, sextet, sextuplet, sise, six, sixer.

VI (noun)	hexad (noun)
more than 130 southeastern Virgin Islands; a dependent territory of the United States	the cardinal number that is the sum of five and one
the cardinal number that is the sum of five and one