Twelve Olympians vs Olympian

Twelve Olympians and Olympian both are nouns.

Word	Noun	Adjective	Verb	Adverb
Twelve Olympians	Yes	No	No	No
Olympian	Yes	Yes	No	No

As nouns, Twelve Olympians and Olympian are synonyms defined as:

Twelve Olympians and Olympian: a classical Greek god after the overthrow of the Titans

Other synonyms of Twelve Olympians include Olympic god.

Twelve Olympians (noun)	Olympian (noun)
a classical Greek god after the overthrow of the Titans	an athlete who participates in the Olympic games
	a classical Greek god after the overthrow of the Titans

Twelve Olympians (adjective)	Olympian (adjective)
	of or pertaining to the greater gods of ancient Greece whose abode was Mount Olympus
	of the region of Olympia in Greece or its inhabitants