The first wedges appeared in the form of stone-cutting tools like knives and axes. Since then, they’ve become larger and stronger. They’ve also become smaller and more delicate.
A wedge is a form of inclined plane. It’s made of two inclined planes placed back to back. Inclined planes don’t move, but wedges do. Wedges are usually used to push things apart. For example, an axe or a nail can split or push apart a piece of wood. The bow of a ship pushes apart water as the ship moves along. A wedge can also be used to tighten or hold things in place. For example, a doorstop is a wedge.