A machine tool in which a rotating cutter, usually a twist drill, is pushed into a workpiece to produce a hole.
A tool used to bore through rock when sinking shafts.
A surgical instrument used to remove a circular section of bone from the skull; a trephine.
To create a large hole by making a narrow groove outlining the shape of the hole and then removing the plug of material remaining by less expensive means.
To use a trepan; to trephine.