A heavy, large core or flake tool of the Palaeolithic period, typically having a wide, straight cutting edge at one end, like a modern ax head. Technologically it is related to the handax, and is often found as a component of Acheulian (esp. Upper Acheulian) handax industries. The sharp transverse cutting edge was almost always notched by use but never sharpened. Along with bifacial tools, it was one of the main instruments of Homo erectus. It is found mainly in Africa, where much of the flake surface is left unretouched. The axlike knife was used since the Middle Pleistocene era to cut through animal bone and meat.