These words pertain to the guns and other military equipment used in fighting wars. Arms and weapons are general terms, nearly interchangeable, for the instruments of combat. A bow-and-arrow, sword or rifle are all arms or weapons . Of the two terms, arms is more frequently restricted in use to those weapons that an individual soldier can wield, whereas weapons are anything used in the fight, from chance sticks and stones to hydrogen bombs. In its most general sense, arms can also refer to the whole military capability of a country: Both nations bankrupted themselves in their foolish race to manufacture arms .

Armament is similar in meaning to this last sense of arms, but it is much clearer in that it points without confusion both to the weapons and the military equipment used to wage war: The country’s armament includes the most versatile planes, the fastest ships and the most rugged tanks in the world. Armament may also be used to refer to the total weapons available to a military vehicle: The destroyer’s armament consists of several small cannon, two torpedo tubes and a number of anti-aircraft guns. Ordnance may be used, like armament , for the total military effort of a country, but much more commonly refers specifically to heavy firearms, mounted cannon or mortars, and other heavy artillery.

Materiel and munitions both refer to equipment rather than to weapons. Materiel suggests all the supporting equipment and supplies necessary to combat, while munitions most commonly suggests ammunition only: Dry socks are as important an item of materiel as munitions .

Arsenal and deterrent have come into fairly recent use to refer to a country’s nuclear arms. Arsenal previously meant simply a place where weapons are stored, but in this specific instance it indicates a stockpile of nuclear warheads. Deterrent is an almost euphemistic word for a nuclear arsenal : The atomic arsenal of either nation alone could lay waste to the entire planet, yet each emerging country clamours to build its own deterrent as well.