parlor grand piano vs baby grand piano

parlor grand piano and baby grand piano both are nouns.

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

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

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

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