gravitational vs gravitation

gravitational is not a noun while gravitation is a noun.

Word	Noun	Adjective	Verb	Adverb
gravitational	No	Yes	No	No
gravitation	Yes	No	No	No

gravitational (noun)	gravitation (noun)
	a figurative movement toward some attraction
	movement downward resulting from gravitational attraction
	(physics) the force of attraction between all masses in the universe; especially the attraction of the earth's mass for bodies near its surface

gravitational (adjective)	gravitation (adjective)
of or relating to or caused by gravitation