Source : Webster's Revised Unabridged Dictionary (1913)

Isolation \I`so*la"tion\, n. [Cf. F. isolation.]
   The act of isolating, or the state of being isolated;
   insulation; separation; loneliness. --Milman.

Source : WordNet®

isolation
     n 1: a state of separation between persons or groups
     2: the act of isolating something; setting something apart from
        others [syn: {closing off}]
     3: a feeling of being disliked and alone
     4: preference for seclusion or isolation [syn: {reclusiveness}]
     5: (psychiatry) a defense mechanism in which memory of an
        unacceptable act or impulse is separated from the emotion
        originally associated with it
     6: a country's withdrawal from internal politics; "he opposed a
        policy of American isolation"