In modern armoured warfare, hull-down is a position taken up by an armoured fighting vehicle (AFV) such that its hull (the main part of the vehicle) is behind a crest or other raised ground, but its turret (or a superstructure or roof-mounted weapon) is exposed. This allows it to observe and fire upon the ground ahead, while the hull is protected from enemy fire behind hard cover. A hull-down AFV is said to be in defilade.