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

France is undertaking a similar international review process for the Nuward SMR, a pressurised water reactor being developed under the leadership of EDF. —Prabhat Ranjan Mishra, Interesting Engineering, 23 Jan. 2026

The administration says that this risk model is too cautious, leading to costly conservatism in reactor design, staffing redundancies and stringency in licensing. —Katy Huff, Scientific American, 23 Jan. 2026

In that context, nuclear—especially small modular reactors (SMRs)—has entered Rwanda’s planning not as a leap of faith, but as a calculated response to scale, reliability, and cost. —Ken Silverstein, Forbes.com, 22 Jan. 2026

In highly technical roles, the market prioritizes domain depth—such as liposome technologies or catalytic reactor techniques—over general management strategy. —Nick Lichtenberg, Fortune, 22 Jan. 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)