diamagnetism

from WordNet (r) 3.0 (2006)

diamagnetism
    n 1: phenomenon exhibited by materials like copper or bismuth
         that become magnetized in a magnetic field with a polarity
         opposite to the magnetic force; unlike iron they are
         slightly repelled by a magnet

from The Collaborative International Dictionary of English v.0.48

Diamagnetism \Di`a*mag"net*ism\, n.
   1. The science which treats of diamagnetic phenomena, and of
      the properties of diamagnetic bodies.
      [1913 Webster]

   2. The magnetic action which characterizes diamagnetic
      substances, the magnetic moments of which tend to oppose
      an externally applied magnetic field. Contrasted with
      {paramagnetism} and {ferromagnetism}.
      [1913 Webster +PJC]