Longman Dictionary of Contemporary English
Wiktionary
n. An accordion with a keyboard similar to that of a piano.
WordNet
n. a portable box-shaped free-reed instrument; the reeds are made to vibrate by air from the bellows controlled by the player [syn: accordion, squeeze box]
Wikipedia
A piano accordion is an accordion equipped with a right-hand keyboard similar to a piano or organ. Its acoustic mechanism is more that of an organ than a piano, as they are both wind instruments, but the term "piano accordion"—coined by Guido Deiro in 1910—has remained the popular nomenclature. It may be equipped with any of the available systems for the left-hand manual.
In comparison with a piano keyboard, the keys are more rounded, smaller, and lighter to the touch. These go vertically down the side, pointing inward, toward the bellows, making them accessible to only one hand while handling the accordion.
The bass piano accordion is a variation of a piano accordion without bass buttons and with the piano keyboard in an octave lower. They typically have around 3 octaves.
Usage examples of "piano accordion".
There were two musicians playing under the single large palm that dominated the St Victoir's old-fashioned dining rooms: a toothless old black man of about eighty playing a fiddle and a pale, pimply boy of no more than thirteen or fourteen sitting on a stool and playing a piano accordion.
The door opened and an elderly man with two teeth, carrying a violin case, entered The Shed, followed by a colourless thin woman, and a dark and greasy man with a piano accordion hanging around his neck on a leather strap.