1.
a device or piece of equipment with a chamber that can be expanded to draw air in and compressed to force the air out
2.
something constructed of a pleated material and able to be expanded and contracted, e.g. the part enclosing the lenses on some cameras or photographic enlargers
3.
a tool used for blowing air into a fire. It consists of a leather bag between two wooden boards that you pull apart and push together.