Mitre  (us miter) —n. 1 tall deeply-cleft headdress worn by bishops and abbots, esp. As a symbol of office. 2 joint of two pieces of wood etc. At an angle of 90°, such that the line of junction bisects this angle. —v. (-ring) 1 bestow a mitre on. 2 join with a mitre. [greek mitra turban]