Definitions of containment:

• noun:   (military) the act of containing something or someone; keeping it from spreading

  Example: "The army was charged with the containment of the rebel forces"

• noun:   (physics) a system designed to prevent the accidental release of radioactive material from a reactor
• noun:   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

  Example: "Containment of communist expansion was a central principle of United States' foreign policy from 1947 to the 1975"