Electro-magnetism \E*lec`tro-mag"net*ism\ n.
   1. magnetism produced by an electric current.
      [WordNet 1.5]

   2. one of the fundamental forces of nature, responsible for
      both electrical and magnetic phenomena. Called also the
      electromagnetic force. Formerly believed to be separate
      phenomena, electricity and magnetism were shown by
      experiment and theory to be different aspects of the
      electromagnetic force. It is responsible for the forces
      generated between magnetically or electrically charged
      objects, and is the fundamental force responsible for the
      characteristics of electromagnetic radiation, including
      light.
      [PJC]

   3. the branch of physics concerned with electromagnetic
      phenomena.
      [WordNet 1.5]