countersunk

/K AW1 N ER0 S UW0 NG K/
verb
  1. 1

    To create such a conical recess.

    โ€œto countersink a hole for a screwโ€

  2. 2

    To cause to sink even with or below the surface.

    โ€œto countersink a screw or bolt into woodworkโ€

adjective
  1. 1

    (of a bolt or screw) That has a flat conical top allowing it to be inserted flush with a surface

Source: https://en.wiktionary.org/wiki/countersink, https://en.wiktionary.org/wiki/countersunk