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

Construction costs historically account for 60% of a reactor’s total price tag, often due to dependencies on manual documentation and spreadsheets that lead to cascading delays across thousands of interdependent tasks. —Aman Tripathi, Interesting Engineering, 21 Nov. 2025

For Constellation Energy, which owns Three Mile Island's lone functioning nuclear power reactor, the federal loan will lower its financing cost to get the mothballed plant up and running again. —CBS News, 19 Nov. 2025

Westinghouse has designed a modern reactor called the AP1000 that can power more than 750,000 homes. —Spencer Kimball, CNBC, 10 Nov. 2025

The report said that the company will not pursue small module reactors in the near term despite international and national efforts to advance the technology because nuclear technology is both new and incredibly costly to deploy. —Sophie Hartley, IndyStar, 10 Nov. 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)