reactor

noun

re·​ac·​tor rē-ˈak-tər 

1

: one that reacts

2

: a device (such as a coil, winding, or conductor of small resistance) used to introduce reactance into an alternating-current circuit

3

a

: a vat for an industrial chemical reaction

b

: a device for the controlled release of nuclear energy (as for producing heat)

Examples of reactor in a Sentence

Recent Examples on the Web

On March 4, the NRC crowed proudly about issuing the first commercial reactor construction permit in a decade — and the first approval for a non-light water reactor in more than 40 years. —Teri Sforza, Oc Register, 6 Mar. 2026

William Tang and Choongseok Chang are using Aurora to simulate plasma flow, edge physics, and reactor-scale challenges tied to ITER, the international fusion project under construction in France. —Neetika Walter, Interesting Engineering, 4 Mar. 2026

The 345-megawatt reactor could generate up to 500 megawatts at its peak, enough for up to 400,000 homes. —Boston Herald Wire Services, Boston Herald, 4 Mar. 2026

Situated in the southeast of the country, the plant is Ukraine's largest and houses six of its 15 operational nuclear power reactors. —Sam Meredith, CNBC, 27 Feb. 2026

Word History

First Known Use

1890, in the meaning defined at sense 1

Phrases Containing reactor

• atomic reactor
• hyper-reactor
• nuclear reactor

Rhymes for reactor

• attractor
• cofactor
• compactor
• contactor
• contractor
• distractor
• extractor
• impactor
• protractor
• redactor
• refractor
• retractor

Kids Definition

reactor

noun

re·​ac·​tor rē-ˈak-tər 

1

: one that reacts

2

: a device for the controlled release of nuclear energy (as for producing heat)

Medical Definition

reactor

noun

re·​ac·​tor rē-ˈak-tər 

1

: one that reacts: as

a

: a chemical reagent

b

: an individual reacting to a stimulus

c

: an individual reacting positively to a foreign substance (as in a test for disease)

reactors to tuberculin

2

a

: a piece of equipment in which a chemical reaction and especially an industrial chemical reaction is carried out

b

: a device for the controlled release of nuclear energy (as for producing heat)