COUNTER n.
A piece of metal, ivory, wood, or bone, used in reckoning, in keeping account of games, etc. The old gods of our own race whose names . . . serve as counters reckon the days of the week. E. B. Tylor. What comes the wool to . . . I can not do it witthout counters. Shak.
COUNTERSINK v. 2 definitions
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.