Is it ensure, insure, or assure?
1650s, from Latin inductor, agent noun from past participle stem of inducere (see induce). Electromagnetic sense begins in 1837.
inductor in·duc·tor (ĭn-dŭk'tər)n.
Something that inducts, especially a device that functions by or introduces inductance into a circuit.
An electrical component or circuit, especially an induction coil, that introduces inductance into a circuit.
A substance that causes an induced reaction. Unlike a catalyst, an inductor is irreversibly transformed in the reaction.