revolver vs six-gun

revolver and six-gun both are nouns.

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

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

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

Other synonyms of revolver include six-shooter.

revolver (noun)	six-gun (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