1. A vacuum pump that removes gas by ionizing the atoms or molecules and adsorbing them on a metal surface.
2. A vacuum pump in which gas molecules are first ionized by electrons that have been generated by a high voltage and are spiraling in a high-intensity magnetic field, and the molecules are then attracted to a cathode, or propelled by electrodes into an auxiliary pump or an ion trap.
3. A pump that ionizes gas molecules wilth high-energy electrons in a high-intensity magnetic field and then deposits them onto a cathode or ejects them into an auxiliary pump or ion trap.
4. In medicine, a complex of proteins located in the cell membrane that is responsible for actively transporting ions across the membrane against a concentration gradient using energy rich ATP (adenosine triphosphate) molecules. Functions in maintaining osmotic balance in cells and in the conduction of nerve impulses.

Adenosine triphosphate (ATP) refers to a nucleotide present in all living cells which serves as an energy source for many metabolic processes and is required for ribonucleic acid synthesis.