n. A unit of surface area equal to 10 ares (that is, 1,000 square metres, or approximately 0.25 acres)
The Century Dictionary and Cyclopedia
n. In the metric system, a superficial measure, equal to ten times the are—that is, a thousand square meters, or very nearly a quarter of an English acre.
Word Usage
"The new dwarf varieties were able to stand two or three times more artificial fertilizer and to provide an increase of yield per decare from the previous maximum of 450 kilos to as much as 800 kilos per decare."