Is “Countersink” a Scrabble word?
Yes
COUNTERSINK
Valid in at least one Scrabble dictionary
Valid in these dictionaries
SOWPODS / CSW
Scrabble UK & International
TWL / NWL
Scrabble North America
Large English Dictionary
General English word list
Meaning of Countersink
noun
1.A cylindrical recess, typically machined around a hole to admit a screw so that it sits flush with a surface.
verb
1.To create such a conical recess.
“to countersink a hole for a screw”
2.To cause to sink even with or below the surface.
“to countersink a screw or bolt into woodwork”