bellows (n.) Look up bellows at Dictionary.com
c.1200, belwes, "a bellows," literally "bags," plural of belu, belw, northern form of beli, from late Old English belg "bag, purse, leathern bottle" (see belly (n.)). Reduced from blæstbælg, literally "blowing bag." Used exclusively in plural since 15c., probably due to the two handles or halves.