What does reactor mean?
A reactor is a device or structure designed to sustain and control a reaction. Its best-known modern use is as a nuclear reactor: an installation containing a fuel core, coolant system, and safety mechanisms that maintain a controlled chain reaction to produce heat, often for generating electricity. The term can also denote a smaller vessel used for chemical or laboratory reactions, or, less commonly, a person perceived as responding emotionally and impulsively. In public discussion, “reactor” often refers more broadly to the plant or installation rather than only to the vessel containing the nuclear core. The nuclear sense dominates, so unrelated uses may evoke nuclear technology or carry the suggestion of something powerful, potentially dangerous, and closely regulated. For a person who responds strongly to circumstances, “reactive” is usually more neutral and more idiomatic.
nounA reactor is a vessel, structure, or device in which a controlled chemical, biological, or nuclear reaction takes place. By extension, the term can refer to the nuclear installation that contains such a device, including its associated systems and personnel.
- A device or structure in which a nuclear chain reaction is sustained, especially for producing energy.
- A vessel or apparatus in which a chemical or other reaction is carried out.
- A person regarded as reacting strongly or emotionally to events or circumstances.
"The new reactor began generating electricity after passing its safety inspections."
"Safety systems shut down the reactor before its cooling system could fail."
"The laboratory reactor allowed the chemists to test the reaction at unusually high temperatures."
"Critics dismissed him as an emotional reactor who had considered every possible consequence."
The plural is “reactors,” with the same spelling apart from the added s.
"Several reactors use different forms of enriched uranium as fuel."
A nuclear reactor sustains a carefully controlled chain reaction, making one of the smallest and most powerful forms of controlled energy.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does reactor come from?
The word “reactor” was formed from “react,” which combines the Latin prefix re-, meaning “back” or “again,” with agere, meaning “to do” or “act.” It originally referred to a vessel or apparatus in which a reaction took place. The word later acquired its dominant modern association with nuclear chain reactions during the development of nuclear technology in the 20th century.
Related word forms
How reactor is actually used
In contemporary usage, the word usually denotes a nuclear reactor or a facility containing one. The sense meaning an emotionally reactive person is comparatively uncommon and may sound informal, dated, or mildly dismissive.