countersink

nouns

a hole (usually in wood) with the top part enlarged so that a screw or bolt will fit into it and lie below the surface
countersink
is a type of (narrower)
an opening deliberately made in or through something
hole
a bit for enlarging the upper part of a hole
counterbore, countersink, countersink bit

verbs

insert (a nail or screw below the surface, as into a countersink)
countersink, set