the great charter that King John of England was forced by the English barons to grant at Runnymede, June 15, 1215, traditionally interpreted as guaranteeing certain civil and political liberties
See Magna Carta in American Heritage Dictionary 4
or Mag·na Char·ta(măgˈnə kärˈtə)
noun
The charter of English political and civil liberties granted by King John at Runnymede in June 1215.
A document or piece of legislation that serves as a guarantee of basic rights.