a portable box-shaped free-reed instrument; the reeds are made to vibrate by air from the bellows controlled by the player
"During our cultural festival, the street musician played an old accordion that produced a lively melody as he pumped the bellows back and forth."
A small, portable, keyed wind instrument, whose tones are generated by play of the wind from a squeezed bellows upon free metallic reeds.
"He tuned his accordion before joining the band to ensure the brass reeds produced clear notes when he pumped the bellows."
To fold up, in the manner of an accordion
"The wrinkled fabric on his pants had become so soft and loose that it folded up like an accordion when he sat down."
The word accordion comes from the German Akkordeon, which is derived from the French accord meaning "harmony." This French term originally meant "to tune" and traces back to the Italian accordare.