adj. That has a flat conical top allowing it to be inserted flush with a surface
the GNU version of the Collaborative International Dictionary of English
past-participle. Chamfered at the top; -- said of a hole.
past-participle. Sunk into a chamfer.
past-participle. Beveled on the lower side, so as to fit a chamfered countersink.
Word Usage
"A surgeon drilled an inch and a half into my skull, countersunk a ceramic-encased microchip behind my left ear, and threaded sixteen electrodes into my inner ear."