1.That which is contained; the extent; the substance. (Obs.) "The containment of a rich man's estate."
3.(Diplomacy) The act or policy of restricting the influence or territorial growth of a hostile nation. Note: The policy of containment is employed when the defeat of a hostile nation or overthrow of its government is considered impractical or too costly.
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.
5.A structure surrounding a nuclear power plant designed to prevent release of radioactive materials into the environment in the event of an accident.