Definition of bellows

• n. sing. & pl. - 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.
• n. sing. & pl. - 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.