1. Nickname `red beard' given to the Holy Roman emperor Frederick I, and also to two brothers, Horuk and Khair-ed-Din, who were Barbary pirates. Horuk was killed by the Spaniards 1518; Khair-ed- Din took Tunis 1534 and died in Constantinople 1546. 2. Operation German code name for the plans to invade the USSR during World War II in 1941.