Bellows \Bel"lows\, n. sing. & pl. [OE. bely, below, belly, bellows, AS. b[ae]lg, b[ae]lig, bag, bellows, belly. Bellows is prop. a pl. and the orig. sense is bag. See Belly.]

An instrument, utensil, or machine, which, by alternate expansion and contraction, or by rise and fall of the top, draws in air through a valve and expels it through a tube for various purposes, as blowing fires, ventilating mines, or filling the pipes of an organ with wind.

Bellows camera, in photography, a form of camera, which can be drawn out like an accordion or bellows.

Hydrostatic bellows. See Hydrostatic.

A pair of bellows, the ordinary household instrument for blowing fires, consisting of two nearly heart-shaped boards with handles, connected by leather, and having a valve and tube.

Source: Webster's Revised Unabridged Dictionary (1913)