Pump noun,# any of various piston-operated or other devices for forcing or driving liquids or gases into or out of something, etc. a standing device with a handle that is worked up and down for raising water from beneath the ground, especially one serving as the water supply to a community. a a device for forcing air into a tyre; b in compounds • bicycle pump • foot pump. (also petrol pump) a device for raising petrol from an underground storage tank to fill a vehicle's petrol tank. verb (pumped