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.

3. Physics Electromagnetic radiation used to raise atoms or molecules to a higher energy level.

4. Informal The heart.

5. Informal The place where consumers purchase gasoline. Used with the:gas prices rising at the pump.

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.

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.