"small, keyed, bellows-like wind instrument," 1830, from German Akkordion, from Akkord "musical chord, concord of sounds," from a verb similar to Old French acorder "agree, be in harmony," from Vulgar Latin *accordare (compare Italian accordare "to attune a musical instrument;" see accord (v.)), with suffix on analogy of clarion, etc. Invented 1829 by piano-maker Cyrill Demian of Vienna. The type with a keyboard instead of buttons is a piano accordion. Related: Accordionist.