Tlaloc ('tɬaː.loːk) was an important deity in Aztec religion, a god of rain, fertility, and water. He was a beneficent god who gave life and sustenance, but he was also feared for his ability to send hail, thunder and lightning, and for being the lord of the powerful element of water. In Aztec iconography he is normally depicted with goggle eyes and fangs. He was associated with caves, springs and mountains. He is known for having demanded child sacrifices.
In Aztec cosmology, the four corners of the universe are marked by "the four Tlalocs" (Nahuatl: Tlālōquê tɬaː.'loː.keʔ) which both hold up the sky and functions as the frame for the passing of time. Tlaloc was the patron of the Calendar day Mazatl and of the trecena of Ce Quiyahuitl (1 Rain). In Aztec mythology, Tlaloc was the lord of the third sun which was destroyed by fire.
In the Aztec capital Tenochtitlan, one of the two shrines on top of the Great Temple was dedicated to Tlaloc. The High Priest who was in charge of the Tlaloc shrine was called "Quetzalcoatl Tlaloc Tlamacazqui". However the most important site of worship to Tlaloc was on the peak of Mount Tlaloc, a 4100 metres high mountain on the eastern rim of the Valley of Mexico. Here the Aztec ruler came and conducted important ceremonies once a year, and throughout the year pilgrims offered precious stones and figures at the shrine.
Tlaloc was also associated with the watery world of the dead, and with the earth. His name is thought to be derived from the Nahuatl word tlālli "earth", and its meaning has been interpreted as "path beneath the earth", "long cave" or "he who is made of earth". J. Richard Andrews interprets it as "one that lies on the land", identifying Tlaloc as a cloud resting on the mountaintops. Other names of Tlaloc were Tlamacazqui ('Giver') and Xoxouhqui ('Green One'); and (among the contemporary Nahua of Veracruz) Chaneco.
With Chalchiuhtlicue, he was the father of Tecciztecatl. He had an older sister named Huixtocihuatl. He ruled over the third of the five worlds in Aztec belief. In Salvadoran mythology, he was also the father of Cipitio.