Adze

An adze is an ancient type of "edge tool". It dates back to the stone age. 
Adzes are used for smoothing or carving wood in hand woodworking. They are similar to an axe, but with the head mounted perpendicular (at right angles) to the handle. The cutting edge was made from chipped flint in the Mesolithic, polished stone in the Neolithic, and metal later on.
A very similar (but blunt) tool used for digging in hard ground is called a mattock.