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

Another change from other similar reactors is its use of chloride, rather than fluoride salts. —Christopher McFadden, Interesting Engineering, 26 Dec. 2025

Kashiwazaki-Kariwa, located about 136 miles northwest of Tokyo, was among 54 reactors shut after the 2011 earthquake and tsunami crippled the Fukushima Daiichi plant in the worst nuclear disaster since Chernobyl. —Reuters, NBC news, 22 Dec. 2025

While fusion has been achieved on Earth, the technology does not yet work at commercial scale and there are no commercial fusion reactors currently in use. —Max Zahn, ABC News, 18 Dec. 2025

With that, Radiant has now racked up more than half a billion dollars to compete in the race to deliver a compact reactor. —Abhimanyu Ghoshal, New Atlas, 18 Dec. 2025

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)