The sharp tip of an arrow is called an arrowhead. Ancient arrowheads were made from carved, sharpened stone and pieces of bone.
If you're an archaeologist, you probably think of an arrowhead as an artifact that you might find, evidence of some ancient society. As long ago as the Stone Age, hunters attached arrowheads to their weapons, and more modern warriors and hunters used arrowheads made of metal. The word comes from arrow, with its Old English root of arwan, and head, from the Old English heafod, "top of the body," but also "top."