Synonyms/Hypernyms (Ordered by Estimated Frequency) of noun counterbore

1 sense of counterbore

Sense 1
counterbore, countersink, countersink bit -- (a bit for enlarging the upper part of a hole)
       => bit -- (the cutting part of a drill; usually pointed and threaded and is replaceable in a brace or bitstock or drill press; "he looked around for the right size bit")