from The American Heritage® Dictionary of the English Language, 4th Edition
- n. A hole with the top part enlarged so that the head of a screw or bolt will lie flush with or below the surface.
- n. A tool for making such a hole.
- transitive v. To make a countersink on or in.
- transitive v. To drive (a screw or bolt) into a countersink.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. a conical recess, typically machined around a hole to admit a screw so that it sits flush with a surface.
- v. to create such a conical recess.
from the GNU version of the Collaborative International Dictionary of English
- transitive v. 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.
- transitive v. To cause to sink even with or below the surface.
- n. An enlargement of the upper part of a hole, forming a cavity or depression for receiving the head of a screw or bolt.
- n. A drill or cutting tool for countersinking holes.
from The Century Dictionary and Cyclopedia
- To form by drilling or turning, as a cavity in timber or other materials, for the reception of the head of a bolt or screw, a plate of iron, etc., in order that it may be nearly or quite flush with the surface: as, to countersink a hole for a screw.
- To cause to sink in any other body so as to be nearly or quite flush with its surface: as, to countersink a screw or bolt by making a depression for its head.
- n. A drill or brace-bit for countersinking, variously made, according as it is to be used on wood, iron, brass, etc.
- n. An enlargement of a hole to receive the head of a screw or bolt.
- n. The recess in the chamber of a gun into which the rim of the cartridge fits.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. a bit for enlarging the upper part of a hole
- v. insert (a nail or screw below the surface, as into a 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
from counter + sink (Wiktionary)