Easton's Bible Dictionary (1897)
Shadow, one of the wives of Lamech, of the line of Cain, and mother of Tubal-cain (Gen. 4:19, 22).
Smith's Bible Dictionary (1863)
(shade).
Hastings' Dictionary of the Bible (1898) & Schaff's Bible Dictionary
ZIL'LAH (shade), one of the wives of Laniech. Gen 4:19, Josh 11:22, Heb 12:23.
Hitchcock's Bible Names (1869)
shadow; the tingling of the ear