\Marque\, n. [F. marque, in lettre de marque letter of
marque, a commission with which the commandant of every armed
vessel was obliged to be provided, under penalty of being
considered a pirate or corsair; marque here prob. meaning,
border, boundary (the letter of marque being a permission to
go beyond the border), and of German origin. See {March}
border.] (Law)
A license to pass the limits of a jurisdiction, or boundary
of a country, for the purpose of making reprisals.
{Letters of marque}, {Letters of marque and reprisal}, a
   license or extraordinary commission granted by a
   government to a private person to fit out a privateer or
   armed ship to cruise at sea and make prize of the enemy's
   ships and merchandise. The ship so commissioned is
   sometimes called a letter of marque.