DICT.TW Dictionary Taiwan

 Coun·ter·sink v. t. [imp. & p. p.  Countersunk p. pr. & vb. n.  Countersinking.]
 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.
 2. To cause to sink even with or below the surface; as, to countersink a screw or bolt into woodwork.