A dunam (Ottoman Turkish: دونم; Turkish: dönüm), also known as a donum or dunum and as the old, Turkish, or Ottoman stremma, was the Ottoman unit of area equivalent to the Greek stremma or English acre, representing the amount of land that could be ploughed by a team of oxen in a day. The legal definition was "forty standard paces in length and breadth", but its actual area varied considerably from place to place, from a little more than 900 m² in Palestine to around 2500 m² in Iraq.
The unit is still in use in many areas previously ruled by the Ottomans, although the new or metric dunam has been redefined as exactly one decare (1000 m²), in line with the modern Greek royal stremma.
The name dönüm, from the Ottoman Turkish dönmek (دونمك, "to turn") appears to be a calque of the Byzantine Greek stremma and had the same size. It was likely adopted by the Ottomans from the Byzantines in Mysia-Bithynia.
Albania, Bosnia and Herzegovina, Serbia, Montenegro
In Bosnia and Herzegovina and also Serbia, the unit is called dulum (дулум) or dunum (дунум). In Albania it is called dynym or dylym. It is equal to 1,000 square meters.
In Cyprus, the donum is 14,400 square feet (1,338 m2). In the Republic of Cyprus older Greek Cypriots also still refer to the donum, although this is gradually being replaced by another local Greek Cypriot dialect word, σκάλες ['skales], rather than the mainland Greek word stremma. However, officially Cyprus uses the square metre.
Syria, Israel, Palestine, Jordan, Lebanon and Turkey
In Israel, The Palestinian Territories, Syria, Jordan, Lebanon and Turkey the dunam is 1,000 square metres (10,764 sq ft), which is 1 decare. Before the end of the Ottoman Empire and during the early years of Palestine, the size of a dunam was 919.3 square metres (9,895 sq ft), but in 1928, the metric dunam of 1,000 square metres (0.10 ha) was adopted, and this is still used.
A metric dönüm is equal to:
- 1,000 square metres (exactly)
- 10 ares (exactly)
- 1 decare (exactly)
- 0.1 hectares (exactly)
- 0.001 square kilometres (exactly)
The Byzantine Greek stremma was the probable source of the Turkish unit; in modern Greece, the "royal stremma" is likewise equal to 1000 m². The zeugarion (Turkish çift) was a similar unit derived from the area plowed by a team of oxen in a day. The English acre was originally similar to both units in principle, although it developed separately.
- 1 E3 m² for further comparisons
- Conversion of units
- Feddan, a similar non-SI unit of area used in Egypt, Sudan, and Syria.
- Resm-i donum, a land tax based on the area of a farm.
- V.L. Ménage, Review of Speros Vryonis, Jr. The decline of medieval Hellenism in Asia Minor and the process of islamization from the eleventh through the fifteenth century, Berkeley, 1971; in Bulletin of the School of Oriental and African Studies (University of London) 36:3 (1973), pp. 659-661. at JSTOR (subscription required)
- Cowan, J. Milton; Arabic-English Dictionary, The Hans Wehr Dictionary of Modern Written Arabic (4th Edition, Spoken Languages Services, Inc.; 1994; p. 351)
- Ménage, op.cit.
- Λεξικό, 1998
- Costas Lapavitsas, "Social and Economic Underpinning of Industrial Development: Evidence from Ottoman Macedonia", Ηλεκτρονικό Δελτίο Οικονομικής Ιστορίας 
- Мерне јединице у КЗ и КН (in Serbian). Republic Geodetic Authority of the Republic of Serbia. Retrieved 6 September 2010.
- Department of Lands and Surveys web site http://www.moi.gov.cy/moi/dls (retrieved April 2014)
- El-Eini, Roza I.M. (2006). "Currency and Measures". Mandated landscape: British imperial rule in Palestine, 1929-1948. Routledge. p. xxiii. ISBN 978-0-7146-5426-3. Retrieved 2009-05-05.
- Israel Central Bureau of Statistics. "explanatory notes" (PDF). Retrieved 2 August 2013.
- Λεξικό της κοινής Νεοελληνικής (Dictionary of Modern Greek), Ινστιτούτο Νεοελληνικών Σπουδών, Θεσσαλονίκη, 1998. ISBN 960-231-085-5