An electrical switch, in a generator or motor, that periodically reverses the direction of an electric current.

plural of commutator

(mathematics, of a binary operation) Such that the order in which the operands are taken does not affect their image under the operation.

(formal or archaic) Substitution of one thing for another; interchange.

(US) The process or habit of journeying to and from work on a regular basis; commuting.

(transitive, finance, law) To pay, or arrange to pay, in advance, in a lump sum instead of part by part. / (transitive, law, criminology) To reduce the sentence previously given for a criminal offense.

A regular journey between two places, typically home and work. / The route, time or distance of that journey.

(intransitive, US, UK, Canada) To regularly travel from one's home to one's workplace or school, or vice versa.

One who commutes (etymology 1). / (US, UK, Canada) To and from work and home. / (Philippines) Using public transport.

simple past tense and past participle of commute