countersink

[ verb, noun koun-ter-singk; verb koun-ter-singk ]
/ verb, noun ˈkaʊn tərˌsɪŋk; verb ˌkaʊn tərˈsɪŋk /

verb (used with object), coun·ter·sank, coun·ter·sunk, coun·ter·sink·ing.

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 into a prepared depression so as to be flush with or below the surface.

noun

a tool for countersinking a hole.
a countersunk hole.

QUIZZES

HEED THE VOX POPULI, AND TAKE THIS WORD OF THE DAY QUIZ!

Test your memory on these verbal firecrackers from the week of June 29 to July 5!
Question 1 of 7
anchorite

Origin of countersink

First recorded in 1810–20; counter- + sink
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2020

British Dictionary definitions for counter-sinking

countersink
/ (ˈkaʊntəˌsɪŋk) /

verb -sinks, -sinking, -sank or -sunk (tr)

to enlarge the upper part of (a hole) in timber, metal, etc, so that the head of a bolt or screw can be sunk below the surface
to drive (a screw) or sink (a bolt) into such an enlarged hole

noun

Also called: countersink bit a tool for countersinking
a countersunk depression or hole
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012