noun
defending forces; defense unit
Refers to a military unit or group of troops tasked with defense.
防御部隊が敵の攻撃を食い止めた。
The defending forces held off the enemy attack.
攻撃部隊 is an attacking unit, while 防御部隊 is a defending unit.
Compound of 防御 (defense) and 部隊 (unit, corps).