The Collaborative International Dictionary
Countersunk \Coun"ter*sunk`\ (-s?nk`), p. p. & a. from Countersink.
Chamfered at the top; -- said of a hole.
Sunk into a chamfer; as, a countersunk bolt.
Beveled on the lower side, so as to fit a chamfered countersink; as, a countersunk nailhead.
Countersink \Coun"ter*sink`\ (koun"t[~e]r*s[i^][ng]k`; 277), v. t. [imp. & p. p. Countersunk (-s[u^][ng]k`); p. pr. & vb. n. Countersinking.]
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.
To cause to sink even with or below the surface; as, to countersink a screw or bolt into woodwork.
Wiktionary
(context of a bolt or screw English) That has a flat conical top allowing it to be inserted flush with a surface v
(past participle of countersink English)
WordNet
See countersink
n. 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
a bit for enlarging the upper part of a hole [syn: counterbore, countersink bit]
v. insert (a nail or screw below the surface, as into a countersink) [syn: set]
[also: countersunk, countersank]
Usage examples of "countersunk".
He was using one of the big rusty screwdrivers to scratch the wood-filler from the sockets above the countersunk screws.
The pictorial bands were in countersunk low relief, their background being depressed about two inches from the original wall surface.
It was countersunk with exaggerated depth in bands following the same general line as the sparse car-touches of the earlier sections, but the height of the reliefs did not reach the level of the general surface.
The gate was a miniature version of the Thrall's, vertically raised and lowered by countersunk centre-holed millstones.
The edge was countersunk as if for a hinge, but no sign of that or the gate itself remained.
He had not realized that the whole dome was countersunk this far into the lunar plain, thus reducing the amount of roof structure necessary.