<p><strong>Noun</strong></p><ul><li>a keyboard instrument, precursor of the piano, in which the strings are plucked by leather or quill points connected with the keys, in common use from the 16th to the 18th century, and revived in the 20th.</li></ul><p><strong>Adjective</strong></p><ul><li>having a fold or folds like the bellows of an accordion: accordion roof; accordion panel.</li></ul><p><strong>Verb (used without object)</strong></p><ul><li>(of a door, roof, or other covering) to open by folding back or pressing together in the manner of an accordion: The roof of the car accordions to let in sunlight and fresh air.</li><li>to fold, crush together, or collapse in the manner of an accordion.</li></ul><p><strong>Verb (used with object)</strong></p><ul><li>to demolish by crushing together lengthwise: The impact accordioned the car beneath the truck.</li></ul>