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

To evaluate critical hardware With full authorization in place, Oklo will use the reactor to train operators and evaluate critical hardware. — Aman Tripathi, Interesting Engineering, 12 Nov. 2026

The site will also serve as a platform to train personnel for future reactor deployments. — Fred Imbert, CNBC, 11 Nov. 2026

This film takes Godzilla back to his nuclear origins, raising the stakes with a subplot where his heart, which functions like a reactor, threatens to overheat and cause a nuclear meltdown. — Katie Rife, Entertainment Weekly, 9 Nov. 2026

It will be powered by a Radioisotope Thermoelectric Generator (RTG) reactor, which relies on heat generated by a decaying nuclear isotope, and so does not rely on solar power for energy. — Richard Tribou, The Orlando Sentinel, 8 Nov. 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

• acter
• actor
• factor
• tractor
• attractor
• cofactor
• compactor
• contactor
• contractor
• distractor
• extractor
• impactor

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)