countersink

1 of 2

verb

coun·​ter·​sink ˈkau̇n-tər-ˌsiŋk How to pronounce countersink (audio)
countersunk ˈkau̇n-tər-ˌsəŋk How to pronounce countersink (audio) ; countersinking

transitive verb

1
: to make a countersink on (a hole)
2
: to set the head of (something, such as a screw) at or below the surface

countersink

2 of 2

noun

1
: a bit or drill for making a funnel-shaped enlargement at the outer end of a drilled hole
2
: the enlargement made by a countersink

Illustration of countersink

Illustration of countersink
  • countersink 1

Examples of countersink in a Sentence

Recent Examples on the Web
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
Verb
Use a combination drill bit/countersink to bore pilot holes in the shelf and top, then drive screws to fasten them in place [12/13]. Neal Barrett, Popular Mechanics, 5 June 2021 Lay out the holes first and drill and countersink them. Popular Science, 9 Aug. 2020
Noun
This set of countersink drill bits includes five different sizes, as well as a rotating depth stop to prevent any accidental damage to your workplace. Alex Rennie, Popular Mechanics, 2 Dec. 2022 One of the key features to notice is how the movement bridge beveling varies in its proximity to the countersinks – everything from relatively distant, to just barely touching at their exact edges, to actually flowing across a countersink proper. Jack Forster, Bloomberg.com, 20 Jan. 2021 If screw heads sit slightly above the surface, remove, countersink, and screw back in. The Editors Of House Beautiful, House Beautiful, 11 Feb. 2015

Word History

First Known Use

Verb

1816, in the meaning defined at sense 1

Noun

1816, in the meaning defined at sense 1

Time Traveler
The first known use of countersink was in 1816

Browse Nearby Words

Cite this Entry

“Countersink.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/countersink. Accessed 9 Sep. 2025.

Kids Definition

countersink

1 of 2 verb
coun·​ter·​sink ˈkau̇nt-ər-ˌsiŋk How to pronounce countersink (audio)
countersunk -ˌsəŋk How to pronounce countersink (audio) ; countersinking
1
: to make a countersink on (a hole)
2
: to set the head of (as a screw) at or below the surface

countersink

2 of 2 noun
1
: a bit or drill for making a countersink
2
: a funnel-shaped enlargement at the end of a drilled hole
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