Chamfer

A chamfer is a beveled edge connecting two surfaces. If the surfaces are at right angles, the chamfer will typically be symmetrical at 45 degrees. (By contrast, a fillet is the rounding off of an interior corner, and a rounding of an exterior corner is called a “round” or a “radius”.)

“Chamfer” is a term commonly used in mechanical and manufacturing engineering. Special tools such as chamfer mills and chamfer planes are available. In tile work, or furniture such as counters or table tops, an edge or arris that has been eased by rounding instead of chamfering is called a bullnose. Where a chamfer does not go to the end of the piece, but “lifts out” in a smooth curve, the end is called a lark’s tongue.

Source Wikipedia