counterbore

Plural: counterbores

Noun

a bit for enlarging the upper part of a hole
A cylindrical recess, typically machined at the mouth of a hole to admit a screw (such as a cap screw) so that the screw sits flush with a surface.
The cutter used to cut such a recess. (Also used, at less depth, for spotfacing.)

Verb

To create such a cylindrical recess.

Origin / Etymology

From counter- (“against”) + bore (“hole”).

Synonyms

countersink, countersink bit

Scrabble Score: 15

counterbore: not valid in Scrabble (US) TWL Dictionary
counterbore: not valid in Scrabble (MW) Merriam-Webster Dictionary
counterbore: valid Scrabble Word in International Collins CSW Dictionary

Words With Friends Score: 19

counterbore: valid Words With Friends Word