marque (n.)

"action or right of seizure of persons or of property of subjects of a foreign ruler or state by way of reprisal for injuries committed by such persons," early 15c., in letters of marque "official permission to capture enemy merchant ships," from Anglo-French mark (mid-14c.), via Old French from Old Provençal marca "reprisal," from marcar "seize as a pledge, mark," probably from a Germanic source (compare Old High German marchon "delimit, mark;" see mark (n.1)), but the sense evolution is difficult.