baby grand piano vs parlour grand

baby grand piano and parlour grand both are nouns.

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

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

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

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