Source : Webster's Revised Unabridged Dictionary (1913)

Containment \Con*tain"ment\, n.
   That which is contained; the extent; the substance. [Obs.]

         The containment of a rich man's estate.  --Fuller.

Source : WordNet®

containment
     n 1: a policy of creating strategic alliances in order to check
          the expansion of a hostile power or ideology or to force
          it to negotiate pecefully; "containment of communist
          expansion was a central principle of United States'
          foreign policy from 1947 to the 1975"
     2: (physics) a system designed to prevent the accidental
        release of radioactive material from a reactor
     3: (military) the act of containing something or someone;
        keeping it from spreading; "the army was charged with the
        containment of the rebel forces"