bel·lows / ˈbelōz/ • pl. n. [also treated as sing.] 1. a device with a bag that emits a stream of air when squeezed: ∎  (also pair of bellows) a kind with two handles used for blowing air at a fire. ∎  a kind used in a harmonium or small organ.2. an object or device with concertinaed sides to allow it to expand and contract, such as a tube joining a lens to a camera body.

bellows

bellows instrument used to blow a fire. ME. belwes, belows, pl. of belu, below, prob. repr. OE. pl. belga, belgum, of bel(i)ġ, bæl(i)ġ BELLY, which in late OE. occurs as abbrev. of earlier blæstbel(i)ġ ‘blowing-bag’ = ON. blāstrbelgr; see BLAST, BELLY.