countersink

From counter- +‎ sink.

countersink (plural countersinks)

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

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

1. (transitive) To create such a conical recess.

   to countersink a hole for a screw

2. (transitive) To cause to sink even with or below the surface.

   to countersink a screw or bolt into woodwork

• counterbore
• sink
• spotface