n. A mass, usually of soft iron, but sometimes of some other magnetic metal, as nickel or cobalt, rendered temporarily magnetic by being placed within a coil of wire through which a current of electricity is passing. The metal is generally in the form of a bar, either straight, or bent into the shape of a horseshoe. [ 1913 Webster ]
a. Of or pertaining to electromagnetism. [ 1913 Webster ]
Electro-magnetic engine,
Electro-magnetic theory of light (Physics),
n.