parlor vs sitting room

parlor and sitting room both are nouns.

Word	Noun	Adjective	Verb	Adverb
parlor	Yes	No	No	No
sitting room	Yes	No	No	No

As nouns, parlor and sitting room are synonyms defined as:

parlor and sitting room: a room in a private house or establishment where people can sit and talk and relax

Other synonyms of parlor include front room, living-room, living room, parlour.

parlor (noun)	sitting room (noun)
reception room in an inn or club where visitors can be received	a room in a private house or establishment where people can sit and talk and relax
a room in a private house or establishment where people can sit and talk and relax