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

These activities are intended to support the commercial readiness of the fuel for use in existing heavy-water reactor designs. —Aman Tripathi, Interesting Engineering, 19 Apr. 2026

Bronson, with the atomic scientists group, also said nuclear plants are vulnerable during conflicts, citing recent instances where reactors were specifically targeted during the Iran war and the Russia-Ukraine War. —ABC News, 17 Apr. 2026

The six Elwood gas turbines that are heading south are the equivalent of one of Dresden’s reactors in terms of capacity. —The Editorial Board, Chicago Tribune, 17 Apr. 2026

In their efforts to win the race, the Soviets push their reactors too hard, prompting a meltdown — the NASA crew mounts a bold rescue mission, taking their Soviet counterparts on board. —Richard Edwards, Space.com, 17 Apr. 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

• 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)