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

The findings even suggest that modest design modifications can yield substantial benefits, offering engineers flexibility in designing future reactors by balancing performance with engineering complexity. —Aman Tripathi, Interesting Engineering, 6 Sep. 2025

Electricity production at the Paluel nuclear plant in northern France was almost halved on Wednesday after the number 4 reactor was shut down and power at the number 3 reactor was reduced to protect infrastructure at the plant, according to a statement from provider EDF. —Theo Burman shane Croucher, MSNBC Newsweek, 4 Sep. 2025

Molten salt reactors, in particular, seem to offer the best potential for long-term, emission-free operations. —Michael Verdon, Robb Report, 3 Sep. 2025

Tarnowsky estimates that this process is highly efficient and that a one-gigawatt reactor would produce enough tritium per year to run 800,000 homes, or 10 times as much as a fusion reactor of the same thermal power could make. —New Atlas, 2 Sep. 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)