This article records tradition as it has been passed down and reported. Its sources are not yet part of the atlas's verified catalogue.
A tonalpohualli day sign entry records one of the twenty named signs, Crocodile, Wind, House and the rest, that combine with the numbers one through thirteen to name every day of the two hundred and sixty day Mesoamerican calendar, considered for its documented attributes and the fate or character the tradition assigned to a day or a person born under it. Diego Duran's sixteenth century Book of the Gods and Rites, drawing on informants close to the pre conquest priesthood, records these day signs and their assigned meanings as part of a real, documented ritual and divinatory system rather than as folklore recovered secondhand.
An entry records a sign's documented name and its usual pictorial form, and the character, favorable, dangerous, mixed, that Duran's sources and comparable colonial period accounts attribute to it, since the surviving sources sometimes differ in the specific fate they assign the same sign.
Where a sign's meaning is filtered through a colonial period Spanish source rather than a pre conquest one, an entry says so plainly, since Duran himself wrote after the conquest and his informants' knowledge passed through a documented colonial context worth naming rather than treating the account as an unmediated original source.