• Diadem
  Diadem
  Diadem may refer to:*Diadem, a type of crown-Military:*HMS Diadem was a 64-gun third rate ship of the line in the Royal Navy launched in 1782 at Chatham and participated in the Battle of Cape St Vincent in 1787...
  
  , a type of crown

Military

• HMS Diadem
  HMS Diadem (1782)
  HMS Diadem was a 64-gun third rate ship of the line of the Royal Navy, launched on 19 December 1782 at Chatham. She participated in the Battle of Cape St Vincent in 1797.In 1798 she was converted to serve as a troopship...
  
   was a 64-gun third rate ship of the line in the Royal Navy launched in 1782 at Chatham and participated in the Battle of Cape St Vincent in 1787
• HMS Diadem
  HMS Diadem (1896)
  HMS Diadem was the lead ship of the Diadem-class of protected cruiser in the Royal Navy. She was built at Fairfield Shipbuilding & Engineering Co Ltd, Govan and launched on 21 October 1896. She served in the First World War with her sisters. In 1914 she was a stokers' training ship, and was...
  
   was the lead ship of the Diadem-class of protected cruiser in the Royal Navy launched in 1896
• HMS Diadem
  HMS Diadem (84)
  HMS Diadem was a Dido-class light cruiser of the Bellona subgroup of the Royal Navy. She was a modified Dido design with only four turrets but improved AA armament - aka Dido Group 2. She was built by R. and W. Hawthorn, Leslie and Company, Limited , UK), with the keel being laid down on 15...
  
   was a Dido-class cruiser of the Royal Navy in World War II, launched in 1942, and transferred to Pakistan in 1956 as Babur.
• Operation Diadem
  Operation Diadem
  Operation Diadem, also referred to as the Fourth Battle of Monte Cassino was an offensive operation undertaken by the Allies in May 1944, as part of the Italian Campaign. It was launched at 2300 Hours on 11 May 1944 to break the German defenses on the western half of the Winter Line and open up...
  
  , a military operation in World War II's Italian Campaign

Arts and entertainment

• Diadem (book series)
  Diadem (book series)
  Diadem is a series of fantasy novels by John Peel.The series takes place on several different worlds, collectively referred to as the Diadem. Travel between worlds is accomplished through the use of magic portals. The physical distance between worlds is irrelevant. Portal travel is based on the...
  
  , a series of books by John Peel
• The Diadem Saga, a science fiction series by Jo Clayton
  Jo Clayton
  Jo Clayton was an American fantasy and science fiction author. She wrote 35 novels and many short stories. Her works sold over a million copies....
  
  
• "Diadems," a song by Megadeth on the soundtrack
  Demon Knight (soundtrack)
  Demon Knight is the official soundtrack to the 1995 horror film, Demon Knight. It was released on January 10, 1995 through Atlantic Records and mostly consisted of heavy metal and alternative rock...
  
   of the film Demon Knight

Animals

• Diademed monkey, another name for Blue Monkey
  Blue Monkey
  The blue monkey or diademed monkey is a species of Old World monkey native to Central and East Africa, ranging from the upper Congo River basin east to the Great Rift Valley and south to northern Angola and Zambia...
  
   or Pluto Monkey (Cercopithecus mitis)
• Diadem Roundleaf Bat
  Diadem Roundleaf Bat
  The Diadem Leaf-nosed Bat or Diadem Roundleaf Bat is one of the most widespread species of bat in the family Hipposideridae. It is probably most closely related to Hipposideros demissus from Makira and to Hipposideros inornatus from the Northern Territory in Australia...
  
   (Hipposideros diadema)
• Mograbin Diadem Snake
  Mograbin Diadem Snake
  The Mograbin diadem snake is a species of snake in the Colubridae family.It is found in Algeria, Morocco, Tunisia, its natural habitats are subtropical or tropical, dry shrubland, rocky areas, arable land, and pastureland....
  
   (Spalerosophis dolichospilus)
• Diadems, the butterfly genus Hypolimnas
  Hypolimnas
  Hypolimnas is a genus of tropical brush-footed butterflies commonly known as eggflies or diadems. The genus contains approximately 23 species, most of which are found in Africa, Asia, and Oceania. One species, the Danaid Eggfly Hypolimnas is a genus of tropical brush-footed butterflies commonly...
  
  
• Diadem spider, the European garden spider
  European garden spider
  The European garden spider, diadem spider, cross spider, or cross orbweaver is a very common and well-known orb-weaver spider in Europe and parts of North America, in a range extending from New England and the Southeast to California and the northwestern United States and adjacent parts of...
  
   (Araneus diadematus), so called from its crown-shaped markings

Other

• Diadem (star) is the brightest star in the constellation Coma Berenices.
• Diadem Peak
  Diadem Peak
  Diadem Peak is a peak located in the Sunwapta River Valley of Jasper National Park, Canada. Diadem Peak is essentially the high point of a ridge leading down from the slightly higher Mount Woolley...
  
  , a mountain in Alberta, Canada
• DIAdem, a technical software for managing, analyzing, and reporting technical data from National Instruments
  National Instruments
  National Instruments Corporation, or NI , is an American company with over 5,000 employees and direct operations in 41 countries. Headquartered in Austin, Texas, it is a producer of automated test equipment and virtual instrumentation software...