A spear is a pole weapon consisting of a shaft, usually of wood, with a pointed head. The head may be simply the sharpened end of the shaft itself, as is the case with fire hardened spears, or it may be made of a more durable material fastened to the shaft, such as flint, obsidian, iron, steel or bronze. The most common design for hunting or combat spears since ancient times has incorporated a metal spearhead shaped like a triangle, lozenge, or leaf. The heads of fishing spears usually feature barbs or serrated edges. The word spear comes from the Old English spere, from the Proto-Germanic speri, from a Proto-Indo-European root *sper- "spear, pole".Spears can be divided into two broad categories: those designed for thrusting in melee combat and those designed for throwing (usually referred to as javelins). The spear has been used throughout human history both as a hunting and fishing tool and as a weapon. Along with the axe, knife, and club it is one of the earliest and most important tools developed by early humans. As a weapon, it may be wielded with either one hand or two. It was used in virtually every conflict up until the modern era, where even then it continues on in the form of the bayonet, and is probably the most commonly used weapon in history.