Ключевые слова: 88, back keys, black, body, brown, case, cast iron, cast steel wire, felt strips, front keys, grand piano, hammer piano, hammers, heating, ivory, jazz, key, keyboard, keyboard instrument, keys, keystroke, lid, mechanics, moonlight sonata, music stand, octave, old, pedals, pegs, piano, piano action, piano sound, pianoforte, plate, ragtime, resonance, room wall, sound, soundboard, soundpost, strings, timbre, touch, under keys, upper keys, wall, wood, yellowed,