Vestment of an archbishop's office; a band or belt worn round the shoulders with a flap or lappet front and back; by transference, the office of archbishop. The pallium was taken from the shrine of St Peter, which signified that the new archbishop's authority had been delegated by the apostle's successors. [< Lat. pallium = a cloak (worn by philosophers)] -
Dictionary of Medieval Terms and Phrases. Christopher Coredon with Ann Williams.