leviathan (n.) Look up leviathan at Dictionary.com
late 14c., "sea monster, sea serpent," also regarded as a form of Satan, from Late Latin leviathan, from Hebrew livyathan "dragon, serpent, huge sea animal," of unknown origin, perhaps related to liwyah "wreath," from root l-w-h- "to wind, turn, twist." Of powerful persons or things from c.1600. Hobbes's use is from 1651.