Pet form of Margaret, now also used as an independent given name. In the Middle Ages the short form Mag(g) was common, as a result of the early loss in pronunciation of the English preconsonantal r; it is no longer used as a given name, but it did give rise to the surname Maggs.
German, Dutch, and Swedish: from Middle High German krōn(e) ‘garland’, ‘chaplet’, ‘diadem’, Swedish krona (from Latin corona). As a German surname it may have been a habitational name for someone who lived in a house with this sign or a nickname for a bald or tonsured man. The Swedish surname, on the other hand, is probably an ornamental name.