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

Small modular reactors are fundamentally different from the large, bespoke nuclear plants of the past. —Anna Demeo, Forbes.com, 31 May 2026

This program verifies magnet performance before the parts are locked into the main reactor. —Aman Tripathi, Interesting Engineering, 30 May 2026

San Onofre’s reactors powered off forever in 2012, and their decommissioning was announced in 2013. —Teri Sforza, Oc Register, 28 May 2026

Today, the state leads the nation in nuclear energy, generating more electricity from its 11 reactors across six plants than any other state, according to an analysis from the U.S. Energy Information Administration. —Christiana Freitag, Chicago Tribune, 18 May 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)