baby grand vs parlor grand piano

baby grand and parlor grand piano both are nouns.

Word	Noun	Adjective	Verb	Adverb
baby grand	Yes	No	No	No
parlor grand piano	Yes	No	No	No

As nouns, baby grand and parlor grand piano are synonyms defined as:

Other synonyms of baby grand include baby grand piano, parlor grand, parlour grand, parlour grand piano.

baby grand (noun)	parlor grand piano (noun)
a small grand piano	a small grand piano