noun
- a person or thing that reacts or undergoes reaction.
- Electricity. a device whose primary purpose is to introduce reactance into a circuit.
- Immunology, Veterinary Medicine. a patient or animal that reacts positively towards a foreign material.
- 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.
- Chemistry. (especially in industry) a large container, as a vat, for processes in which the substances involved undergo a chemical reaction.
noun
- chem a substance, such as a reagent, that undergoes a reaction
- short for nuclear reactor
- a vessel, esp one in industrial use, in which a chemical reaction takes place
- a coil of low resistance and high inductance that introduces reactance into a circuit
- med a person sensitive to a particular drug or agent
“one that reacts,” 1835, agent noun in Latin form from react. In nuclear sense, attested from 1945.