active defense

active layered theatre (ballistic) missile defense (ALTBMD)

active antimissile defense

active ballistic missile defense

active satellite defense

active air defense

perimeter defense (all-around defense)

beach defense mine / beach-defense mine

active camouflage

active combat area

active component

active component headquarters

active counterintelligence measures

active countermeasures

active deception measures

active decontamination

active defenses

active denial system

active infrared (IR) guidance system

active material; fissile material

active military service

active missile defence

active public information policy

active radar homing (ARH)

active service/ duty

advanced active homing technique

entry on active duty

semi-active homing guidance system

semi-active laser (homing) (SAL/H)

separate from active service / the service

strategic active stockpile

active nutation damping

units to round-out the active Army