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]WordNet (r) 3.0 (2006):
hectare n 1: (abbreviated `ha') a unit of surface area equal to 100 ares (or 10,000 square meters)