Tannin is the name of a demon or dragon in Jewish mythology.
The name developed in modern Hebrew tannin (תנין) literally means crocodile or alligator, from tan (תנ) the stem for hidden or foul lizards or snakes. See tanshemet.
Tannin is represented as a dragon or a serpent.
Sometimes he is compared with Rahab, who is especially associated with the Red Sea. Some scholars associated Tannin with Tiamat, as it happened with Rahab. It is unclear in Jewish literature the differentiation between Tannin, Rahab, and Leviathan, but Tannin and Rahab are more easily confused one with the other.
Tannin, as well as Rahab, was a name applied to Egypt after the exodus of the Israelites from that country.