downhole

[ doun-hohl ]
/ ˈdaʊnˌhoʊl /

noun

a hole dug or drilled downward, as in a mine or a petroleum or gas well.

adjective

occurring or situated in such a hole.

Origin of downhole

British Dictionary definitions for downhole

downhole
/ (ˈdaʊnˌhəʊl) /

adjective

(in the oil industry) denoting any piece of equipment that is used in the well itself