Leviathan in Wikipedia
Leviathan. - The word Leviathan (Hebrew, líweyãthãn), which occurs six times in the Hebrew Bible, seems to have puzzled not a little all ancient translators. The D.V. has kept this name, Job, iii, 8; xl, 20; Is., xxvii, 1; it is rendered by dragon Ps. lxxiii (Hebr., lxxiv), 14, and ciii (Hebr., civ), 26; The word leviathan means:
(1) crocodile (Job 40:20 and Psalm 73:14);
(2) a sea-monster (Psalm 103:26, Isaiah 27:1);
(3) possibly the Draco constellation (Job 3:8).
(4) a Dinosaur, possibly the Kronosaurus.