countersink

English edit

From counter- +‎ sink.

countersink (plural countersinks)

a cylindrical recess, typically machined around a hole to admit a screw so that it sits flush with a surface.

a conical recess machined around a hole

countersink (third-person singular simple present countersinks, present participle countersinking, simple past countersank or countersunk, past participle countersunk)

(transitive) To create such a conical recess.
to countersink a hole for a screw
(transitive, intransitive) To cause to sink even with or below the surface.
to countersink a screw or bolt into woodwork
- 2010, Larry Pardey, Details of Classic Boat Construction, pages 7-30:
  I countersank into the locust just enough to make the nailhead flush.

to create a conical recess