Definitions for: Commutator

[n] switch for reversing the direction of an electric current

Webster (1913) Definition: Com"mu*ta`tor, n. (Elec.)
A piece of apparatus used for reversing the direction of an
electrical current; an attachment to certain electrical
machines, by means of which alternating currents are made to
be continuous or to have the same direction.

See Also: electric switch, electrical switch, switch