[noun koun-ter-mahrk; verb koun-ter-mahrk]Numismatics
Also called counterstamp. a sign or device stamped on a coin after its minting.
verb (used with object)
to stamp (a coin) with a countermark; counterstamp.
Origin of countermark
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019