auger bit

(design engineering) a A bit shaped like an auger but without a handle; used for wood boring and for earth drilling.
(mining engineering) Hard steel or tungsten carbide-tipped cutting teeth used in an auger running on a torque bar or in an auger-drill head running on a continuous-flight auger.

A bit having a square tang, fitted into and rotated by a brace; used for drilling holes in wood.