Wordnet 3.0
NOUN (1)
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;
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]
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