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

Lyman raised concerns about new reactor designs with positive void coefficients, including the Kemmerer Unit 1. —Georgina Jedikovska, Interesting Engineering, 26 Apr. 2026

Bags of sand were dropped onto the reactor from the open doors of helicopters (analysts now think this did more harm than good). —The Week Uk, TheWeek, 26 Apr. 2026

Second, the reactors can run 90% of the time, whereas windmills can only generate power when wind speeds are right. —Mark Dee, Idaho Statesman, 13 Apr. 2026

This discrepancy came to be known as the reactor antineutrino anomaly. —Quanta Magazine, 8 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

• 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)