concertina definition by Webster's New World
Webster's New World College Dictionary Copyright © 2010 by Wiley Publishing, Inc., Cleveland, Ohio. Used by arrangement with John Wiley & Sons, Inc.
a musical instrument similar to an accordion but smaller and with buttons instead of a keyboard
Origin: concert plush -ina: coined (1829) by Sir Charles Wheatstone (1802-75), Eng physicist
concertina definition by American Heritage Dictionary
A small hexagonal accordion with bellows and with buttons for keys.
Origin: concert + Italian -ina, feminine diminutive suff.