Definitions

1. noun

A hole or depression made by a counterboring tool, typically larger in diameter than the hole it replaces, often used to provide space for a screw head or a bearing.

“The engineer specified a counterbore in the metal plate to accommodate the large screw head.”

2. verb

To make a hole or depression with a counterboring tool.

“The machinist counterbored the metal to fit the new component.”