n.
1.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
2.a bit for enlarging the upper part of a hole countersink v.
1.insert (a nail or screw below the surface, as into a countersink)
Idiom of the Day
slow on the uptake
to be slow to figure something out
The new employee is slow on the uptake and we must explain everything to him at least two times.