#security systems
- Air defense — The feminine form of the adjective 'antiaerian', or used as a noun to designate the entire complex of air defense forces, weaponry, artillery, and missile systems dedicated to protecting airspace against enemy aerial attacks.
- Defense — The act of protecting against an attack, aggression, or danger and its result; a set of tactical, strategic measures or fortified structures designed to repel an enemy offensive. In the legal field, it represents the totality of arguments, evidence, and activities carried out by a lawyer to demonstrate an accused person's innocence, while in sports it defines a team's tactics or department responsible for preventing the opponent from scoring.