Commutator

Noun

commutator

(plural commutators)

an electrical switch, in a generator or motor, that periodically reverses the direction of an electric current
(mathematics) (of a group) an element of the form ''ghg

âˆ’1h^âˆ’1 where g and h are elements of the group; it is equal to the group's identity if and only if g and h'' commute

(mathematics) (of a ring) an element of the form ab-ba, where a and b are elements of the ring, it is identical to the ring's zero element if and only if a and b commute