countersink

/ˌkaʊntərˈsɪŋk/

Other forms: countersunk; countersinking; countersinks

Definitions of countersink

1. verb

   insert (a nail or screw below the surface, as into a countersink)
   synonyms: set

   type of:

   bury, sink

   embed deeply
2. noun

   a hole (usually in wood) with the top part enlarged so that a screw or bolt will fit into it and lie below the surface
   type of:

   hole

   an opening deliberately made in or through something
3. noun

   a bit for enlarging the upper part of a hole
   synonyms: counterbore, countersink bit

   type of:

   bit

   the cutting part of a drill; usually pointed and threaded and is replaceable in a brace or bitstock or drill press