■ verb ( past and past participle countersunk ) enlarge and bevel the rim of (a drilled hole) so that a screw or bolt can be inserted flush with the surface.
↘drive (a screw or bolt) into such a hole.
COUNTERSINK
Meaning of COUNTERSINK in English
Concise Oxford English vocab. Сжатый оксфордский словарь английского языка. 2004