Reactor

How to spell reactor

7 letters · 3 syllables

How to pronounce reactor

Say the part in capitals loudest.

What does reactor mean?

1. nounA large apparatus or vessel in which a controlled reaction takes place, especially the core of a nuclear power plant.

Reactor in a sentence

• The nuclear reactor supplies most of the region's electricity.

• Engineers shut down the reactor for routine maintenance.

Where does reactor come from?

Language of origin: Latin

The word is built on the verb 'react', which English assembled in the 1600s from the Latin prefix re-, meaning 'back' or 'again', and agere, the Latin verb 'to do, to drive, to act'. To react was literally 'to act back', that is, to respond to a force or stimulus with an answering action. The agent suffix -or, also from Latin, turns a verb into the thing that performs it, just as it does in 'actor', 'motor', and 'conductor'. 'Reactor' itself is a fairly modern coinage, appearing in chemistry and engineering for a vessel in which reactions are made to take place, and it leapt into general use during the 1940s with the rise of the nuclear reactor. The spelling stays regular throughout: the everyday root 'act' sits visibly in the middle, so the trap is simply remembering the -or ending rather than the more common -er.

How the word is built

• re- (back, again)
• act (from Latin agere: to do, drive, act)
• -or (agent/instrument suffix)