Definition of dunam:
(n) :
A modern Turkish unit of surface area equal to a decare (1000 m²), equivalent to the modern Greek stremma.
(n) :
Various other units in other areas of the former Ottoman Empire, usually equated to the decare but sometimes varying (as in Iraq, where it is 2500 m²).
(n) :
(historical) An Ottoman Turkish unit of surface area nominally equal to 1,600 square (Turkish) paces but actually varied at a provincial and local level according to land quality to accommodate its colloquial sense of the amount of land able to be plowed in a day, roughly equivalent to the Byzantine stremma or English acre.