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

Instead of building new reactors to produce plutonium, agencies can extract Americium from existing waste, a form of recycling at a planetary scale. —Kaif Shaikh, Interesting Engineering, 14 Nov. 2025

In fact, Oklo’s reactor — to rise within view of the silver dome that contained EBR-II — will use fuel recycled from the former reactor’s waste. —Brandon Loomis, AZCentral.com, 12 Nov. 2025

The push for modern nuclear technology in the form of small module reactors known as SMRs comes alongside a steep rise in demand for energy. —Sophie Hartley, IndyStar, 10 Nov. 2025

Valar broke ground on a site for a test reactor in September at the Utah San Rafael Energy Lab, a unit of the Utah Office of Energy Development. —Spencer Kimball, CNBC, 10 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)