The Collaborative International Dictionary
Myriare
Myriare \Myr"i*are\, n. [F. See Myria-, and 2d Are.] A measure of surface in the metric system containing ten thousand ares, or one million square meters. It is equal to about 247.1 acres.
Wiktionary
myriare
n. A metric measure of surface equal to 10,000 ares, or one million square metres.