See Also: counterbore(1)(dictionary)
counterbore(2)(dictionary)

counterbore(1) (iou)



counterbore noun. L19.
[from COUNTER- 2 + BORE noun1.]
A drilled hole that has a flat-bottomed enlargement at its mouth. L19.
A drill whose bit has a uniform smaller diameter near the tip, for drilling counterbores in one operation. L19.