Easton's Bible Dictionary (1897)
A floor; bottom, a place between Adar and Azmon, about midway between the Mediterranean and the Dead Sea (Josh. 15:3).
Hastings' Dictionary of the Bible (1898) & Schaff's Bible Dictionary
KARKA'A (foundation), a southern boundary of Judah, Josh 15:3, and therefore of the Holy Land itself.
Hitchcock's Bible Names (1869)
floor; dissolving coldness