say it: ree-AK-tur
reactor is a noun meaning "an electrical device used to introduce reactance into a circuit". It carries 2 recorded senses.
an electrical device used to introduce reactance into a circuit
(physics) any of several kinds of apparatus that maintain and control a nuclear reaction for the production of energy or artificial elements
physics
Forms marked · are formed by the regular rule rather than recorded in the source data. English keeps a few hundred irregulars and the rest follow the pattern, so the rule is right far more often than not — but it is a rule, and the mark says so.
Definitions, synonyms and semantic relations for reactor come from Princeton University’s WordNet. The pronunciation comes from the CMU Pronouncing Dictionary. Commonness is measured against a corpus of everyday English. Full sources and licences.