A dunam (Ottoman Turkish: ?; 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",[1] but its actual area varied considerably from place to place, from a little more than in Ottoman Palestine to around in Iraq.[2][3]
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 , which is 1/10 hectare (1/10 × , like the modern Greek royal stremma.[3]
The name dönüm, from the Ottoman Turkish dönmek (, "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.[4]
The Dictionary of Modern Greek defines the old Ottoman stremma as approximately ,[5] but Costas Lapavitsas used the value of for the region of Naoussa in the early 20th century.[6]
In Bosnia and Herzegovina and also Serbia, the unit is called dulum () or dunum (). In Bosnia and Herzegovina dunum (or dulum) equals . One dulum is equal to for the region of Leskovac, south Serbia. In Albania it is called dynym or dylym. It is equal to 1,000 square meters.[7]
In Bulgaria, the decare () is used.
In Cyprus, a donum is 14,400 square feet (1,340 m2).[8] 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, ['skales], rather than the mainland Greek word stremma (equivalent to a decare). However, officially Cyprus uses the square metre and the hectare.[]
A donum consists of 4 evleks, each of which consists of 3,600 square feet (330 m2).[]
In Greece, the old dönüm is called a "Turkish stremma", while today, a stremma or "royal stremma" is exactly one decare, like the metric dönüm.[3]
In Iraq, the dunam is 2,500 square metres (0.25 ha).[9]
In Israel, Palestine, 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 the British Mandate for 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.[10][11]
The Dubai Statistics Center and Statistics Centre Abu Dhabi use the metric dunam (spelt as donum) for data relating to agricultural land use.[12] One donum equals 1000m2.
Other countries using a dunam of some size include Libya and Syria.[]
The metric dunam is particularly useful in hydrological calculations as 1 dönüm times 1 mm (a unit commonly used for measuring precipitation) equals exactly one cubic meter.
The Byzantine Greek stremma was the probable source of the Turkish unit. 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.[]