[{"Bold_text": "verb (used with object)", "List Items": ["to enlarge the upper part of (a cavity), especially by chamfering, to receive the cone-shaped head of a screw, bolt, etc.", "to cause (the head of a screw, bolt, etc.) to sink a prepared depression so as to be flush with or below the surface."]}, {"Bold_text": "noun", "List Items": ["a tool for countersinking a hole.", "a countersunk hole."]}]