(
DoD,
NATO) The act of maintaining a continuous receiver watch with transmitter calibrated and available, but not necessarily available for immediate use.
(
DoD,
NATO) The action by land, air, or sea forces to protect by offense, defense, or threat of either or both.
(
DoD,
NATO) Those measures necessary to give protection to a person, plan, operation, formation, or installation from the enemy intelligence effort and leakage of information.
(
DoD,
NATO) Shelter or protection, either natural or artificial.
Department of Defense Dictionary of Military and Associated Terms. 31 January 2011.