tannin

This word names a large serpentine creature that inspires dread. Its center of gravity is the dragon of the sea and the deep, the monster other ancient peoples imagined as a rival to their gods. The Bible takes that figure and turns it inside out: on the fifth day God simply creates it, like the fish and the birds, so it is a creature and not a god. From there it becomes a picture, again and again, of the powers that threaten God's order, and finally of the empires that crush Israel, until God hooks it, breaks its heads, and slays it.

The same word can also drop down to ground level and mean an ordinary venomous serpent, the kind whose bite is poison. Hebrew pairs it there with the cobra, and the danger is real and immediate rather than cosmic. This is not a different word but the smaller end of one range: a serpent, whether the snake in the dust or the dragon in the sea.

Between those poles sits the wonder before Pharaoh, where the staff becomes a tannin, a grand and menacing serpent that swallows the serpents of Egypt's magicians. The reader is meant to feel the size and threat of the creature, the same threat God will later level at Pharaoh himself, who is called this very monster crouching in his river.

The Greek Old Testament rendered the word almost everywhere as dragon, and that choice carried the Hebrew monster straight into the dragon of Revelation, so the small Hebrew word ended up linking creation, history, and the end of all things.