Solenoid

[Sarah]

An electrodynamic spiral having the conjuctive wire turned backalong its axis, so as to neutralize that component of the effect ofthe current which is due to the length of the spiral, and reduce thewhole effect to that of a series of equal and parallel circularcurrents. When traversed by a current the solenoid exhibits polarityand attraction or repulsion, like a magnet.

[Sarah]

You call it an electromagnet, clever engineers call it a solenoid.

A length of wire wound around a ferrous core. The assembly becomes magnetic when a current is passed through the wire.