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

Nuclear power reactor operators also break six figures, with an annual median salary of $122,890. — Itzel Franco, CNBC, 2 Oct. 2026

That standard reaction produces high-energy neutrons, which wear down reactor walls over time. — Aman Tripathi, Interesting Engineering, 2 Oct. 2026

The reactor, known as Ward 250, received rapid approval this year after the Department of Energy conducted a quiet overhaul of its internal safety and security regulations for nuclear reactors. — Geoff Brumfiel, NPR, 30 Sep. 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)