Tonalli

Tonalli is a concept central to the cosmology of the Aztec and other Nahua peoples of Mesoamerica. It is often translated as "day," "heat," "sun," or "soul," but its meaning is multifaceted and encompasses a vital essence or spiritual energy. Tonalli was believed to be imprinted upon an individual at birth, determined by the day sign of their birth calendar, known as the tonalpohualli. This birth tonalli was thought to influence a person's destiny, personality, and inherent qualities.

The tonalli was also associated with the sun and its life-giving heat. It was considered a potent force that could be bestowed or absorbed. For example, a newborn was said to receive their tonalli from the sun. Conversely, individuals could lose tonalli through extreme fear, illness, or exhaustion, which could lead to sickness or even death. Rituals and practices were often aimed at preserving or replenishing one's tonalli. This vital energy was also thought to be shared or transferred among individuals and objects. The concept of tonalli underscores a worldview where the spiritual and physical realms were deeply interconnected, and where personal destiny was intimately linked to cosmic forces.