Definition of borehole

i. A hole with a drill, auger, or other tools for exploring strata in search of minerals, for water supply, for blasting purposes, for proving the position of old workings and faults, and for releasing accumulations of gas or water.

ii. A circular hole made by boring; esp. a deep hole of small diameter, such as an oil well or a water well. Also called well bore.

See Also: hole