countersink

to widen the top of the hole for a screw or bolt so that the head will fit into the hole and be level with or below the surface

to place screws, bolts, or nails in wood or another material so that their heads are level with or below the surface of the material

a hole for a screw or bolt that is wider at the top so that the head will fit into the hole and be level with or below the surface

a special drill bit or other tool for countersinking holes for screws or bolts