Ahuitzotl was the eighth Aztec ruler, the Huey Tlatoani of the city of Tenochtitlan, son of princess Atotoztli II. His name literally means "Water Thorny" and was also applied to the otter. It is also theorized that more likely, the animal called ahuitzotl is actually the water opossum, the hand symbolizing its prehensile tail, which otters notably lack.

Tlahtoāni is a historical title used by the dynastic rulers of āltepēmeh, autonomous political entities formed by many pre-Colombian Nahuatl-speaking peoples in the Valley of Mexico during the Postclassic Period. The title of huēyi tlahtoāni was used by the rulers of the Aztec Empire, an alliance between the āltepēmeh of Tenochtitlan, Tetzcoco, and Tlacopan.