Mantle

1. The royal cloak or mantle of a sovereign is fashioned out of gold doubled with ermine.

The mantles worn by peers in the House of Lords are termed Parliamentary Robes. The rank of the bearer is distinguished by the number of rows or guards of ermine on the mantle: a Duke has four rows; a Marquis, three and a half; a Viscount, two and a half; and a Baron, two. Those of a Viscount and Baron are plain white fur.

2. The name given to the foldage or great cloak, derived from the French Manteau, or long robe, whereon achievements are painted and is thus an accessory  to an Achievement of Arms. The mantle is often mounted with a crown or coronet denoting the rank of the bearer.

See also Pavilion and compare with Mantling.