A Turret is an armoured structure consisting of a barbette that crosses the armor of whatever it is mounted on, and a gunhouse for protecting the weapon's loading mechanism. In the EDF series, the term could potentially refer to several things which do not fit that description:
For the "Vehicle" in Earth Defense Force: Insect Armageddon, see Turret (Vehicle)
For the Tactical Armor's deployable sentry guns, see Turret (Ability)
For the deployable sentry guns in other EDF games, see ZE-GUN