teyolia.

Literally, the teyolia, or "someone's animator" was "commonly identified in the sixteenth-century with 'the soul' (e.g. Molina 1970, 95). There was a good reason for this: it was considered by the Nahuas to be part of the self that survived mortal life, and, unlike the unstable tonalli--always subject to being scared off, by a sudden fright or other disturbing experience, and possessing an independent volition--it was the vivifying force part excellence, that one could never abandon the living being." As something centered in the heart, "it shared with it its qualities of cognition, sentimentality, and desire.. But like the heart, the teyolia was susceptible to those diseases that originated with illicit sexual acts or excesses, which were said to compress or darken the heart, or that were caused by sorcerers who magically devoured or 'twisted' hearts." One could straighten out the heart through neyolmelahualiztli.
J. Jorge Klor de Alva, "Aztec Spirituality and Nahuatlized Christianity," in South and Meso-American Native Spirituality, ed. Gary H. Gossen in collaboration with Miguel Leeo_Portilla (New York: Crossroad, 1993), 184.

teyolia = someone's soul
Susanne Klaus, Uprooted Christianity: The Preaching of the Christian Doctrine in Mexico, Based on Franciscan Sermons of the 16th Century Written in Nahuatl (Bonn: Bonner Amerikanistische Studien e. V. c/o Seminar für Völkerkunde, Universität Bonn, 1999), 247.