Hectare

from WordNet (r) 3.0 (2006)

hectare
    n 1: (abbreviated `ha') a unit of surface area equal to 100 ares
         (or 10,000 square meters)

from The Collaborative International Dictionary of English v.0.48

Hectare \Hec"tare`\, n. [F., fr. Gr. ? hundred + F. are an are.]
   A measure of area, or superficies, containing a hundred ares,
   or 10,000 square meters, and equivalent to 2.471 acres.
   [1913 Webster]