A magnet is a material or object that produces a magnetic field. The name derives from the Greek μαγνήτης λίθος (magnétes líthos), that is “Magnesia stone,” from the name of a place in Asia Minor, known since ancient times for the huge deposits of magnetite.

A permanent magnet is an object made from a material that is magnetized and creates its own persistent magnetic field. The materials that can be magnetized are also those strongly attracted to a magnet, and are called ferromagnetic (or ferrimagnetic); these include iron, nickel, cobalt, some rare earth alloys and some natural minerals such as magnetite. Even if ferromagnetic (and ferrimagnetic) materials are the only ones attracted by a magnet so intensely as to be commonly considered “magnetic”, all substances weakly respond to a magnetic field, through one of the numerous types of magnetism.