[ koun-ter-bawr, -bohr; koun-ter-bawr, -bohr ]

  1. a tool for enlarging a drilled hole for a portion of its length, as to permit sinking a screw head.

  2. the portion of the hole so enlarged.

verb (used with object),coun·ter·bored, coun·ter·bor·ing.
  1. to enlarge (a drilled hole) along part of the length of the hole by drilling with a bit having a greater diameter.

Origin of counterbore

First recorded in 1605–15; counter- + bore2

Other words from counterbore

  • coun·ter·bor·er, noun

Words Nearby counterbore Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2024

How to use counterbore in a sentence