bellows
A device for delivering pressurized air 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.
Example
“When wood fires were common, so were bellows for helping start them.”
Other meanings
Any flexible container or enclosure, as one used to cover a moving joint.
Flexible, light-tight enclosures connecting the lensboard and the camera back.
Word history
From Old English "bæliġ".
Where this comes from
This definition is adapted from “bellows” on Wiktionary, by its contributors, published under CC BY-SA 4.0. This page is published under the same licence.