Leviathan (//; Hebrew: לִוְיָתָן, Modern Livyatan Tiberian Liwyāṯān ; "twisted, coiled") 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 means simply "whale". It is described extensively in Job 41 and mentioned in Isaiah 27:1.
The Leviathan is mentioned six times in the Tanakh, with Job 41:1–34 being dedicated to describing him in detail:
In Psalm 74 God is said to "break the heads of Leviathan in pieces" before giving his flesh to the people of the wilderness; in Psalm 104 God is praised for having made all things, including Leviathan; and in Isaiah 27:1 he is called the "wriggling serpent" who will be killed at the end of time.
Sea serpents feature prominently in the mythology of the Ancient Near East, attested as early as the 3rd millennium BCE in Sumerian iconography depicting the myth of the god Ninurta overcoming the seven-headed serpent. Examples of the storm god vs. sea serpent trope in the Ancient Near East can be seen with Baʿal vs. Yam (Canaanite), Marduk vs. Tiamat (Babylonian), and Atum vs. Nehebkau (Egyptian) among others, with attestations as early as the 2nd millennium as seen on Syrian seals.