The Hebrew noun תנין (tannîyn, pronounced tahn-NEEN), which on two occasions is spelled with a final mem as תנים (tannîym, pronounced tahn-NEEM), is an exciting and rare word, typically translated as "sea monster" or "dragon." The idea of the sea monster is not unique to the Hebrew Bible but is a common occurrence in the mythologies of southwestern Asia and the Levant, appearing prominently in both the Babylonian creation epic the Enuma Elish and the Ugaritic Baal Cycle.

A key similarity between these different traditions is the role of the sea monster as an opponent to be defeated. Therefore, it is not surprising that there are multiple references to the defeat of the תנין (tannîyn) by God in the Hebrew Bible. For example, Isaiah 27:1 says, "On that day the LORD with his cruel and great and strong sword will punish Leviathan the fleeing serpent, Leviathan the twisting serpent, and he will kill the dragon (התנין) that is in the sea." Isaiah 51:9 refers to the conflict differently, stating, "Was it not you who cut Rahab in pieces, who pierced the dragon (תנין)?" Meanwhile, Psalm 74:13 describes the fight like this: "You divided the sea by your might; you broke the heads of the dragons (תנינים) in the waters." However, the Hebrew Bible's inclusion and use of the תנין (tannîyn) is distinct from other Mesopotamian traditions in that the תנין (tannîyn) is listed among the creatures of the waters created by the Hebrew God on the fifth day in Genesis 1:21: "So God created the great sea monsters (התנינם)."

Interestingly, תנין (tannîyn) appears twice in descriptions of foreign leaders, occurring both times in prophetic utterances relaying the words of the Hebrew God. In Jeremiah 51:34, the LORD, speaking for Jerusalem, says through the prophet Jeremiah, "King Nebuchadrezzar [sic] of Babylon has devoured me, he has crushed me; he has made me an empty vessel, he has swallowed me like a monster (כתנין)." In Ezekiel 29:3, תנין (tannîym) appears again, this time referring to the Pharaoh of Egypt: "Thus says the Lord GOD: I am against you, Pharaoh king of Egypt, the great dragon (התנים) sprawling in the midst of its channels." Such references to the dragon are likely intended to call to mind the Lord's conquering of the תנין (tannîyn) in the Psalms and Isaiah, with the intent of bringing assurance that the Lord would act similarly against these individuals.