countersink

v (pt -sank /-sNk; -9sANk/, pp -sunk / -sQNk; -9sQNk/) [Tn usu passive通常用於被动语态 ] 1 enlarge the top of (a hole) so that the head of a screw or bolt fits into it level with or below the surrounding surface 钻埋头孔. 2 insert (a screw or bolt) into such an enlarged hole 将（螺钉或螺栓）旋入埋头孔中.

counteraction, counterargument, counterbalance, counterbalancing, counterblast, counterclaim, counterfeit, counterfoil, countermand, countermeasure, counterpane, counterpart, counterparts, counterplot, counterpoint, counterpoise, counterproductive, counterproductiveness, countersign, countersignature, countervailing, countess, counting-house, countless, countrified, country, country club, country dance, country house, country seat, country-and-western, country-house, countryman, countryside, county, county council, county court, county town, coup, coup de grace,