Technical senses of obscure origin. short for burr-chisel n., burr-drill n. at compounds (also, a similar instrument used for surgical operations…

a dentist's drill with a serrated or file-cut knob or head.

spec. One used by a dentist to remove tooth material.

A drilling machine operated by a foot pedal; esp. one formerly used in dentistry.

a dentist's drill-stock or drilling-machine.