Magnet

The loadstone; a species of iron ore (the ferrosoferric or magnetic ore, Fe3O4) which has the property of attracting iron and some of its ores, and, when freely suspended, of pointing to the poles; -- called also natural magnet.

A bar or mass of steel or iron to which the peculiar properties of the loadstone have been imparted; -- called, in distinction from the loadstone, an artificial magnet.

(physics) a device that attracts iron and produces a magnetic field