warren Look up warren at Dictionary.com
late 14c., "piece of land enclosed for breeding beasts and fowls," from Anglo-Fr. and O.N.Fr. warenne, O.Fr. garenna "game park," possibly from Gaulish *varenna "enclosed area," related to *varros "post." Or the O.Fr. forms may derive from the prp. of O.Fr. warir "defend, keep," from the Gmc. root *war- "to protect, guard" (source of O.E. warian "take care;" see warrant (n.)). Later esp. "piece of land for breeding of rabbits" (c.1400), which led to the transf. sense of "cluster of densely populated living spaces" (1640s).