bel·lows 
(bĕlōz, -əz)
(bĕlōz, -əz)pl.n. (used with a sing. or pl. verb)
1.
a. An apparatus for producing a strong current of air, as for sounding a pipe organ or increasing the draft to a fire, consisting of a flexible, valved air chamber that is contracted and expanded by pumping to force the air through a nozzle.
b. Something, such as the pleated windbag of an accordion, that resembles this apparatus.
2. The lungs.
[Middle English belowes, from Old English belgas, pl. of belg; see bhelgh- in the Appendix of Indo-European roots.]
bellowsthree-row diatonic accordion