TLALOC, the pan-Mesoamerican deity of rain and fertility, was named by the Aztec, or Mexica, of Central Mexico. They chose a word derived from the Nahuatl term meaning "he is the embodiment of the earth." Other fertility deities throughout Mesoamerica include Chac among the Maya, Cocijo among the Zapotec, Tzahui among the Mixtec, and Tajin among the Totonac. Many of these deities continue to be worshiped by the contemporary indigenous people of Mesoamerica.

Tlaloc made his first appearance at Teotihuacan between 200 and 700 CE. He is depicted iconographically in murals and temples with round, "goggle" eyes and a fanged mouth. He strongly resembles a jaguar, with predatory features. At Teotihuacan, ideas regarding rain, fertility, wealth, and prestige were combined with human sacrifice and warfare.

More detailed textual information exists regarding Tlaloc during the Mexica period (1325–1521 CE). During the calendar year, which for the Aztec consisted of eighteen twenty-day "months...