What is the meaning of Arpen?

Formerly, a measure of land in France, varying in different parts of the country. The arpent of Paris was 4,088 sq. yards, or nearly five sixths of an English acre. The woodland arpent was about 1 acre, 1 rood, 1 perch, English.

Source: Webster’s Revised Unabridged Dictionary (1913), via OPTED