A device for delivering pressurizedair in a controlled quantity to a controlled location. At its most simple terms a bellows is a container which is deformable in such a way as to alter its volume which has an outlet or outlets where one wishes to blow air.
Third-person singular simple present indicative form of bellow
Origin
From Middle English belwes, plural of belu, belwe, a northern form of beli, from Old English belg, cf. bælġ, from Proto-Germanic *balgiz. Compare German Balg. See also belly.