umbrella - a formation of military planes maintained over ground operations or targets; "an air umbrella over England"

military action, action - a military engagement; "he saw action in Korea"

air defense - defensive measures designed to destroy attacking enemy aircraft or missiles or to nullify their effectiveness

stand - a defensive effort; "the army made a final stand at the Rhone"

hasty defence, hasty defense - a defense organized while in contact with the enemy or when time is limited

deliberate defence, deliberate defense - a defensive organized before contact is made with the enemy and while time for organization is available; usually includes a fortified zone (with pillboxes) and communication systems

biodefence, biodefense, biological defence, biological defense - procedures involved in taking defensive measures against attacks using biological agents

chemical defence, chemical defense - procedures involved in taking defensive measures against attacks using chemical agents

minelaying, mining - laying explosive mines in concealed places to destroy enemy personnel and equipment

biological warfare defence, biological warfare defense, BW defence, BW defense - defense against biological warfare

armed forces, armed services, military, military machine, war machine - the military forces of a nation; "their military is the largest in the region"; "the military machine is the same one we faced in 1991 but now it is weaker"