parlor grand piano vs baby grand

parlor grand piano and baby grand both are nouns.

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

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

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

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