Weapons are employed individually or collectively. A weapon can be either expressly designed as such or be an item re-purposed through use (for example, hitting someone with a hammer). Their form can range from simple implements such as clubs to complicated modern implementations such as intercontinental ballistic missiles and biological weapons. Weapon development has progressed from early wood or stone clubs through revolutions in metalworking (swords, maces, etc.) and gunpowder (guns, cannon), electronics and nuclear technology.
In a broader context, weapons may be construed to include anything used to gain a strategic, material or mental advantage over an adversary on land, sea, air, or even outer space or virtual space.