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

Regulators must determine staffing requirements, update safety rules, and address new forms of waste that may arise from reactors using alternative coolants. —Kaif Shaikh, Interesting Engineering, 6 Dec. 2025

The Kudankulam plant in Tamil Nadu already has two of six reactors connected to the grid, with four more under construction. —Hannah Parry, MSNBC Newsweek, 5 Dec. 2025

Other industrial uses In addition to delivering electricity, small modular reactors can also directly generate large amounts of heat. —Leonel Lagos, The Conversation, 3 Dec. 2025

The 835-megawatt reactor can power the equivalent of approximately 800,000 homes, the Department of Energy said. —CBS News, 19 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)