upright vs upright piano

upright and upright piano both are nouns.

Word	Noun	Adjective	Verb	Adverb
upright	Yes	Yes	No	No
upright piano	Yes	No	No	No

As nouns, upright and upright piano are synonyms defined as:

upright (noun)	upright piano (noun)
a piano with a vertical sounding board	a piano with a vertical sounding board
a vertical structural member as a post or stake

upright (adjective)	upright piano (adjective)
upright in position or posture
of moral excellence
in a vertical position; not sloping