Entry 1 sense Webster, 1913 Water lizard /wôt'-ẽr lĭz'-ẽrd/ · Wa·ter liz·ard · IPA 01 n. Any aquatic lizard of the genus Varanus, as the monitor of the Nile. See Monitor, n., 3. 1. Any aquatic lizard of the genus Varanus, as the monitor of the Nile. See Monitor, n., 3.(Zool.) See: Monitor