Definition of "unipolar"

unipolar

adjective
not comparable
1. Having a single pole.
  Quotations
  All that talk of one superpower -- us -- bestriding a "unipolar" world seems as dated as Seinfeld reruns.
  2008 December 31, Michael Kinsley, “The Bush Presidency, Eight Years Later”, in Time‎, archived from the original on 4 January 2009
2. (psychology, medicine) Not both depressive and manic; not bipolar.
  Quotations
  Most studies have tended to find somewhat higher suicide rates in unipolar depression than in bipolar disorder
  2007, Frederick K. Goodwin, Kay Redfield Jamison, Manic-Depressive Illness: Bipolar Disorders and Recurrent Depression, Volume 1, page 250
3. (politics) Of or relating to an international system in which one state wields most of the cultural, economic, and political influence.