n.1. A machine or device for raising, compressing, or transferring fluids.
2. Physiology A molecular mechanism for the active transport of ions or molecules across a cell membrane.
v.tr.1. To cause to flow by means of a pump or pumplike organ or device: Derricks pumped oil out of the ground. The heart pumps blood throughout the body.
2. To draw, deliver, or pour forth: a writer who pumped out a new novel every year.
3. To propel, eject, or insert: pumped new life into the economy.
4. To cause to move with an up-and-down or back-and-forth motion: a bicyclist pumping the pedals; a piston pumping a shaft.
5. To push or pull (a brake or lever, for instance) rapidly: a driver pumping the brakes.
6. To shoot (bullets, for example) at or into: a gunner pumping rounds at a target.
7. Physics To raise (atoms or molecules) to a higher energy level by exposing them to electromagnetic radiation at a resonant frequency.
8. Physiology To transport (ions or molecules) against a concentration gradient by the expenditure of chemically stored energy.
9. To invest (money) repeatedly or persistently in something.
10. To question closely or persistently: pump a witness for secret information.
11. Informal To promote or publicize vigorously: The company pumped its new product on its website.
v.intr.1. To operate a pump.
2. To move gas or liquid with a pump or a pumplike organ or device.
3. To move up and down or back and forth in a vigorous manner: My legs were pumping as I ran up the stairs.
4. To flow in spurts: Blood was pumping from the wound.
5. Sports To fake a throw, pass, or shot by moving the arm or arms without releasing the ball.