1803, from French piano (18c.), Italian piano, shortened forms of pianoforte (q.v.). As an adverb, "softly," in musical directions (superlative pianissimo), attested from 1680s. Piano wire attested from 1831.
A musical direction meaning “to be performed softly”; the opposite of forte. As the name of a musical instrument, it is short for pianoforte.
Spareribs, esp a single section of broiled spareribs: cornbread with a piano on a platter (1940s+ Black)