Dictionary.net

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

(military) the act of containing something or someone; keeping it from spreading; "the army was charged with the containment of the rebel forces"

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 1

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

That which is contained; the extent; the substance.

Provision of physical and biological barriers to the dissemination of potentially hazardous biologically active agents (bacteria, viruses, recombinant DNA, etc.). Physical containment involves the use of special equipment, facilities, and procedures to prevent the escape of the agent. Biological containment includes use of immune personnel and the selection of agents and hosts that will minimize the risk should the agent escape the containment facility.