The surface, usually a shield, upon which bearings are
   marshaled and displayed. The surface of the escutcheon is called the
   field, the upper part is called the chief, and the lower part the base
   (see Chiff, and Field.). That side of the escutcheon which is on the
   right hand of the knight who bears the shield on his arm is called
   dexter, and the other side sinister.