1.  containment(n = noun.cognition) - a policy of creating strategic alliances in order to check the expansion of a hostile power or ideology or to force it to negotiate peacefully; "containment of communist expansion was a central principle of United States' foreign policy from 1947 to the 1975"
Derived form verb contain₆

2.  containment(n = noun.artifact) - (physics) a system designed to prevent the accidental release of radioactive material from a reactor;

3.  containment(n = noun.act) - the act of containing; keeping something from spreading; "the containment of the AIDS epidemic"; "the containment of the rebellion"
Derived form verb contain₆

1.  That which is contained; the extent; the substance. [1913 Webster]

2.  the act of containing. [PJC]

3.  the act or policy of restricting the influence or territorial growth of a hostile nation.

4.  the act of restricting some deleterious substance within a confined space, especially when such material is released unintentionally or by accident; as, containment of nuclear waste; containment of an oil spill. Also used attributively, as a containment boom. [PJC]

5.  a structure surrounding a nuclear power plant designed to prevent release of radioactive materials into the environment in the event of an accident. [PJC]

containment, n. the action or policy of preventing the expansion of a hostile country or influence.