Birûn
was the term used in the Ottoman Empire to designate the "Outer Service" of the imperial court, concerned with the public affairs of the Ottoman sultans, as opposed to the private "Inner Service". Its name derives from the location of its offices in the outer court of the Topkapi Palace, which in turn echoed the arrangements of the palace in Edirne, the Ottomans' second capital.
The scope of the was very extensive. As the Ottomanist Halil İnalcık writes, "The Outside Service comprised all the organizations regulating the sultan's relations with the outside world, comprising governmental and ceremonial offices and the sultan's standing army". The included a number of senior officials, who had typically previously been enrolled as pages, educated in the palace school, and served in the. These were:
- the Agha of the Janissaries, commander of the Janissary Corps
- the Keeper of the Sultan's Standard
- the Chief Doorkeeper and his lieutenant
- the Master of the Horse
- the Chief Falkoner
- the Chief Taster
- the Chief Usher
- the Aghas commanding the household cavalry divisions
- the Chief Armourer
- the Chief Gunner
- the Chief Coachman