Countersink

v. t.	1.	To chamfer or form a depression around the top of (a hole in wood, metal, etc.) for the reception of the head of a screw or bolt below the surface, either wholly or in part; as, to countersink a hole for a screw. [imp. & p. p. Countersunk (-sŭņk`); p. pr. & vb. n. Countersinking.]
	2.	To cause to sink even with or below the surface; as, to countersink a screw or bolt into woodwork.
n.	1.	An enlargement of the upper part of a hole, forming a cavity or depression for receiving the head of a screw or bolt.
	2.	A drill or cutting tool for countersinking holes.

Noun	1.	countersink - 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
	2.	countersink - a bit for enlarging the upper part of a hole Synonyms: counterbore, countersink bit
Verb	1.	countersink - insert (a nail or screw below the surface, as into a countersink) Synonyms: set

bury, set, sink