Definition of countersink
(Entry 1 of 2)
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
nounDefinition of countersink (Entry 2 of 2)
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
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Merriam-Webster unabridged
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Time Traveler for countersink
The first known use of countersink was in 1816
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