Dictionary.net

• In the metric system, a land measure equal to 100 ares or 2.471 acres.

1919 - The Winston Simplified Dictionary
By William Dodge Lewis, Edgar Arthur Singer

• n. [French] A French measure of area, or a superficies, containing a hundred ares, or ten thousand square metres, and equivalent to 2.4711 English acres.

1871 - The Cabinet Dictionary of the English Language