'magnetic monopole' definitions:

Definition of 'magnetic monopole'

From: WordNet
noun
A hypothetical particle with a single magnetic pole instead of the usual two

Definition of 'magnetic monopole'

From: GCIDE
  • magnetic monopole \magnetic monopole\ (Physics), a hypothetical subatomic particle having only one type of magnetic charge, the magnetic analogue of an electrically charged particle; it has only one magnetic pole instead of the two observed in all common magnetic object; -- it was still not observed as of 1998. [PJC]