reactor: Meaning and Definition of

re•ac•tor

1. a person or thing that reacts or undergoes reaction.
2. a device whose primary purpose is to introduce reactance into a circuit.
3. a patient or animal that reacts positively towards a foreign material.
4. Also calledan apparatus in which a nuclear-fission chain reaction can be initiated, sustained, and controlled, for generating heat or producing useful radiation.
5. (esp. in industry) a large container, as a vat, for processes in which the substances involved undergo a chemical reaction.