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

That enrichment level is typically used for commercial nuclear power reactors. —Kevin Breuninger, CNBC, 6 June 2026

Both NextEra and Dominion have also explored expansions of their nuclear fleet through the development of smaller, modular reactors that proponents say will cut down on costs compared to older, highly-individualized reactor designs. —John Moritz, Hartford Courant, 6 June 2026

The reactor is expected to move toward fuel loading and subsequent operational preparations in the coming years. —Prabhat Ranjan Mishra, Interesting Engineering, 3 June 2026

Even excellent operators cannot reliably hold those relationships in their heads in real time, especially across a fleet of reactors running different products at different scales. —Hamid Noori, Forbes.com, 28 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)