containment

Short definition from Wiktionary

Noun

1. 1
   The state of being contained.
2. 2
   The state of containing.
3. 3
   Something contained.
4. 4
   A policy of checking the expansion of a hostile foreign power by creating alliances with other states; especially the foreign policy strategy of the United States in the early years of the Cold War.
5. 5
   A physical system designed to prevent the accidental release of radioactive or other dangerous materials from a nuclear reactor or industrial plant.
6. 6
   An inclusion.