[ree-ak-ter] 
| 1. | a person or thing that reacts or undergoes reaction. |
| 2. | Electricity. a device whose primary purpose is to introduce reactance into a circuit. |
| 3. | Immunology, Veterinary Medicine. a patient or animal that reacts positively towards a foreign material. |
| 4. | Also called atomic pile, chain reactor, chain-reacting pile, nuclear reactor, pile. Physics. an apparatus in which a nuclear-fission chain reaction can be initiated, sustained, and controlled, for generating heat or producing useful radiation. |
| 5. | Chemistry. (esp. in industry) a large container, as a vat, for processes in which the substances involved undergo a chemical reaction. |
| atomic pile n. An early type of nuclear reactor whose core consisted of layers of graphite block interspersed with uranium, designed to create a sustained fission reaction. |
| atomic pile
An early type of nuclear reactor whose core consisted of layers of graphite block interspersed with uranium, designed to create a sustained fission reaction. |