six-gun vs revolver

six-gun and revolver both are nouns.

Word	Noun	Adjective	Verb	Adverb
six-gun	Yes	No	No	No
revolver	Yes	No	No	No

As nouns, six-gun and revolver are synonyms defined as:

six-gun and revolver: a pistol with a revolving cylinder (usually having six chambers for bullets)

Other synonyms of six-gun include six-shooter.

six-gun (noun)	revolver (noun)
a pistol with a revolving cylinder (usually having six chambers for bullets)	a pistol with a revolving cylinder (usually having six chambers for bullets)
	a door consisting of four orthogonal partitions that rotate about a central pivot; a door designed to equalize the air pressure in tall buildings