O.E. hydan, from W.Gmc. *khuthjanan, from PIE *keudh- (cf. Gk. keuthein "to hide, conceal"), from base *(s)keu- "to cover, conceal" (see hide (n.1)). Past participle hidden is a M.E. formation (O.E. had gehydd "hidden") on the model of ride/ridden, etc. Hide and seek (1672) replaced earlier all hid (1588); while hide-out "a hiding place" is Amer.Eng., first attested 1885.
"measure of land" (obsolete), O.E. hid, earlier higid, from hiw- "family" (cf. hiwan "household," hiwo "a husband, master of a household"), from PIE *keiwo- (cf. L. civis "citizen"). The notion was of "amount of land needed to feed one free family and dependents," usually 100 or 120 acres, but the amount could be as little as 60, depending on the quality of the land.