An arrowhead is the sharp piece at the front of an arrow — the part meant to cut or pierce. In older times it was often stone or metal, fitted onto a wooden shaft. Today you meet the word in history class, in museums, and when people talk about hunting. Sport archery often uses a different kind of tip, but the old name still sticks for that pointed shape. People also stretch it, a little loosely, to anything that looks like that point: a road sign, a leaf, a mark on a map. The core meaning is still the working end of the arrow, not the whole arrow, and not a person’s head. Head here is the front piece, the same idea as the head of a nail.