A diadem is a type of crown. Diadem may also refer to: Maritime , several vessels of the Royal Navy Diadem (ship), several merchant vessels Arts and entertainment Diadem (board game), a 1981 science fiction game The Diadem Saga, a science fiction series by Jo Clayton "Diadems", a song by Megadeth on the soundtrack for the film Demon Knight "Diadem", a tune used for the hymn "All Hail the Power of Jesus' Name" Animals Diademed monkey Diadem roundleaf bat Mograbin diadem snake Diadem spider Diadems, the butterfly genus Hypolimnas Diadem (horse), a 20th-century Thoroughbred racehorse Other uses Diadem (star), a star in the constellation Coma Berenices Operation Diadem, a military operation in World War II's Italian Campaign Diadem Peak, a mountain in Alberta, Canada DIAdem, a technical software for managing, analyzing, and reporting technical data from National Instruments See also Diadema (disambiguation)