Meaning : 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.
Meaning : A bit for enlarging the upper part of a hole.
Synonyms : counterbore, countersink bit
Meaning : Insert (a nail or screw below the surface, as into a countersink).
Synonyms : set
Countersink meaning in Bengali (Bangla).