The originally Persian title dewan (also known as diwan, also spelled or devan/ divan) has, at various points in Islamic history, designated a powerful government official, minister or ruler.
The word is Persian in origin and was loaned into Arabic. The original meaning was "bundle (of written sheets)", hence "book", especially "book of accounts," and hence "office of accounts," "custom house," "council chamber". The meaning divan "long, cushioned seat" is due to such seats having been found along the walls in Middle Eastern council chambers.
The divan of the Sublime Porte was the council or Cabinet of the state. In the Ottoman Empire, it consisted of the usually (except in the Sultan's presence) presiding Grand Vizier and other viziers, and occasionally the Janissary Ağa.
In Javanese and related languages, the cognate Dewan is the standard word for council, as in the Dewan Perwakilan Rakyat or (Indonesia's Council of People's Representatives) and Dewan Negara (Senate of Malaysia).
In the Indian subcontinent
Later, when most vassal states gained various degrees of self-determination, the finance — and/or chief minister and leader of many princely states (especially Muslim, but also many Hindu, including Baroda, Hyderabad, Mysore, Kochi, Travancore — referred as Dalawa until 1811) became known as a dewan. See Oswal, Tandon
Exceptionally, a ruler was himself titled Dewan or a loftier variation, notably :
- in Beri-Bundelkhand
- in Dhurwai
- in Jaso (Jassu) and in Bandhora (which was split from the former c. 1750)
- in Khilchipur until 1873, then Rai Bahadur
- in Junagadh, where Shah Nawaz Bhutto was the prime-minister of the former princley state.
- Diwan Sahib or Diwan Bahadur in Garrauli State.
As a title used in various Middle kingdoms of India, Diwan denoted the highest officials in the court after the king; the suffix -ji is added as a mark of respect in India. In the major Maratha kingdoms of Baroda (ruled by the Gaekwad), Gwalior (ruled by Scindias or Shinde), Indore (ruled by Holkar), and Nagpur (ruled by Bhonsle, but not from the Chhatrapati Shivaji family), the highest officer after the king was called the Diwan. One of the example was – Shrimant Diwan/Rao Bahadur Atmaram Kulkarni was the Diwan (Prime Minister) of Jamkhandi state ["The Marathas: 1600 to 1818" by Stewart Gordon, Cambridge University Press]. In the 19th century the British Parliament established in British India a supreme court for revenue matters (non-criminal matters) named the "Sudder Dewanny Adawlut", which applied Hindu law.
Derived and compound titles
Nowadays, the title is used amongst certain upper-middle-class families in South Asia; several landlords in villages and provinces across the subcontinent have names prefixed with this title. The title, in its variant form "Dewan", is especially common amongst Muslim land-owners in Bengal and the Punjab.
Diwan also became a surname of high caste Hindus or Sikhs in Punjab.
After the Battle of Plassey when the Bengal was annexed by the East India Company in 1757, the Moghul King granted the Company the Diwani (the right to collect revenue) in Bengal and Bihar in 1765. The term Diwani thus referred to British (fiscal) suzerainty over parts of India during the early British Raj.
In French India, one of its constituent colonies, Yanaon, had Zamindar and Diwan. They were active in its local and municipal administration during French rule. The Zamindar of Yanam was given a 4 gun salute by French counterparts.
- Zamindar — Manion Canacaya
- Diwan — Bouloussou Soubramaniam Sastroulou
- Sovereignty — French Colonial Empire
The document dated Bikram Samvat 1833 Bhadra Vadi 3 Roj 6 (i.e. Friday 2 August, 1776), shows that Vamsharaj Pande and Swaroop Singh Karki had carried the title of Dewan (equivalent to Prime Minister) of Kingdom of Nepal.
- Thangjam, Homen (Summer 2014). "Militarism, Human Rights, and Democracy in Northeast India". Kangla Lanpung. RK Sanatomba Memorial Trust,Imphal. VIII (II): 27–. ISSN 2321-2357.
- Campbell, Lawrence Dundas (ed), Asiatic Annual Register for 1802, or A View of the History of Hindustan and of the Politics, Commerce and Literature of Asia, London, J. Debrett, 1803, footnote pp.97-100, Miscellaneous Tracts 
- Definition per James Mill (1826): "Dewan, Duan: place of assembly. Native minister of the revenue department; and chief justice, in civil causes, within his jurisdiction; receiver-general of a province. The term is also used, to designate the principal revenue servant under a European collector, and even of a Zemindar. By this title, the East India Company are receivers-general of the revenues of Bengal, under a grant from the Great Mogul"..."Dewanny, Duannee: the office, or jurisdiction of a Dewan" (Mill, James, The History of British India, Vol. 1 (of 6), 3rd Edition, London, 1826, Glossary )
- Robb 2004, pp. 116–147 "Chapter 5: Early Modern India II: Company Raj", Metcalf & Metcalf 2006, pp. 56–91 "Chapter 3: The East India Company Raj, 1772-1850," Bose & Jalal 2003, pp. 76–87 "Chapter 7: Company Raj and Indian Society 1757 to 1857, Reinvention and Reform of Tradition."
- Definition per James Mill (1826): "Dewan, Duan: place of assembly. Native minister of the revenue department; and chief justice, in civil causes, within his jurisdiction; receiver-general of a province. The term is also used, to designate the principal revenue servant under an European collector, and even of a Zemindar. By this title, the East India Company are receivers-general of the revenues of Bengal, under a grant from the Great Mogul"..."Dewanny, Duannee: the office, or jurisdiction of a Dewan" (Mill, James, The History of British India, Vol. 1 (of 6), 3rd Edition, London, 1826, Glossary )
- Regmi 1975, p. 272.