- Present participle of countersink.
Variant of countersink
transitive verbcountersunk, countersinking
- to enlarge the top part of (a hole in metal, wood, etc.) so that the head of a bolt, screw, etc. will fit flush with or below the surface
- to sink the head of (a bolt, screw, etc.) into such a hole
- a bit for countersinking holes
- a countersunk hole