Leviathan

Leviathan is a sea monster referenced in the Tanakh, or the Old Testament. The word has become synonymous with any large sea monster or creature. In literature - e.g., Herman Melville's Moby-Dick - it refers to great whales, and in Modern Hebrew, it simply means "whale". It is described extensively in Job 41 and mentioned in Psalm 104:26 and Isaiah 27:1.