Definition of piano noun from the Oxford Advanced Learner's Dictionary

BrE BrE//piˈænəʊ//
; NAmE NAmE//piˈænoʊ//
(pl. pianos) (old-fashioned, formal pianoforte
BrE BrE//piˌænəʊˈfɔːti//
; NAmE NAmE//piˌænoʊˈfɔːrti//
a large musical instrument played by pressing the black and white keys on the keyboard. The sound is produced by small hammers hitting the metal strings inside the piano. to play the piano playing jazz on the piano piano music a piano teacher/lesson Ravel’s piano concerto in G a sonata for violin and piano Alison Evans provided piano accompaniment. see also grand piano, thumb piano, upright piano See related entries: Musical instruments
Word Originnoun early 19th cent.: from Italian, abbreviation of pianoforte.Extra examples He was sitting at the piano, ready to play. The piece can also be played on the piano. There is a piano bar for evening entertainment. a length of piano wire a piano made by Steinway playing classical music on the piano
See the Oxford Advanced American Dictionary entry: piano