solenoid

Etymology

From French solénoïde, from Ancient Greek σωληνοειδής (sōlēnoeidḗs) (from σωλήν (sōlḗn, “channel, pipe”) + -ειδής (-eidḗs); see -oid).

noun

1. (physics) A coil of wire that acts as a magnet when an electric current flows through it.
2. (engineering) An electromechanical device consisting of such a coil containing a metal core, the movement of which is controlled by the current.
3. (electronics) An electromechanical switch controlled by a solenoid; solenoid switch, relay.
4. (meteorology) The region of intersection between isobaric and isopycnal surfaces.