1610s, "the characteristic properties of a magnet," from Modern Latin magnetismus (see magnet + -ism). Figurative sense of "personal charm, attractive power or influence" is from 1650s; in the hypnotic sense it is from Mesmer (see mesmerism). Meaning "science of magnets and magnetic phenomena" is by early 19c.
magnesia
Magnesian
magnesium
magnet
magnetic
magnetism
magnetite
magnetization
magnetize
magneto
magneto-