Tonalli has three meanings: day, heat of the sun, and luck. 
Tonalli as dayA day in the Anahuaca calendar is a combination of a day number, 1-13 and a day sign, Cipactli-Xochitl. There are 260 unique day signs together known as the tonalpohualli because 260 is the resulting product when 13 is multiplied by 20. This 260 day cycle was used for divination in Pre-Cuauhtemoc times.
Relation to the Xiuhpohualli
The tonalli differs from the cempoalilhuitl because it is considered to be "movable" whereas the cempoalilhuitl is considered to be "fixed." This is the result of the inability to match the tonalpohualli with with the solar year exactly. As a result, in one solar year there is one complete tonalpohualli cycle with 105 additional days. Therefore a particular tonalli such as 5-Cuetzpallin in one solar year will fall in a completely different place in subsequent years and will only fall at the same time of the year every 52 years.
The Movable Feasts 
These feasts are classified as movable because they appear in different places of the xiuhpohualli each year therefore they are not fixed to a particular time of the year. The tonalli is most easily identified within the tonalpohualli by locating first the trecena in which it falls. The tonalli is often referred to as the 1st, 2nd, 3rd etc. house within the trecena in many sources as a result. A person's birth tonalli for example is so inexplicably tied to the fate attached to it that it makes the most sense to celebrate it on the tonalli rather than the actual location within the xiuhpohualli (second day of tlacaxipehualiztli for example).
|4-Ollin||1-Ocelotl||During this feast they offered, to the image of the sun, quail, and they offered incense. And at noon they slew captives before it in honor of the sun. On the same day, all drew blood from their ears-children and those who were grown-in honor of the sun, and they offered it that blood.|
|7-Xochitl||1-Ocelotl||On this day, all the painters and seamstresses celebrated a feast. They fasted some for forty days, others for twenty, in order to prevail over chance, in order to paint well and to weave textiles well. For this purpose they offered quail and incense, and performed other ceremonies-the men to the teotl Chicome Xochitl, and the women to the teotl Xochiquetzal.|
|1-Mazatl||1-Mazatl||On this day, they celebrated a feast to the teteo who are named cihuapipilti, because they said that then they came down to the earth. They adorned their images with papers and offered them offerings.|
|2-Tochtli||1-Mazatl||This feast was dedicated to the teotl Izquitecatl and all the other Teteo of wine. On this day they adorned his image very well on his teocalli, and offered him things to eat, and they sang and played musical instruments before him. And in the courtyard of his teocalli they set a large open jar of wine, and those who were wine merchants filled it to overflowing, and all who wished went to drink. They had some canes through which they drank. The wine sellers kept feeding the large jar, so that it was always full. Mostly, those who had newly cut the maguey did this. The first syrup which they took out they took to the teocalli as first fruits.|
|1-Xochitl||1-Xochitl||This was a great feast in which the leading men and the lords danced and sang in honor of this sign, and they otherwise made merry while adorned with the richest feathers. In this feast the lord gave gifts to the warriors and to the singers and to the palace folk.|
|1-Acatl||1-Acatl||The leading men celebrated a great festival to Quetzalcoatl in the calmecac. On this day they adorned the calmecac with rich ornaments and placed before it offerings of perfumes and food. They said this was the sign of Quetzalcoatl.|
|1-Miquiztli||1-Miquiztli||The lords and leading men celebrated a great feast to Tezcatlipoca and they said this was his sign. Since all of them had their shrines in their houses, where they kept the images of Tezcatlipoca and of many others, on this day they decorated this image and offered it perfumes, flowers, and food, and sacrificed quail before it, tearing off their heads. This not only the lord and leading men did, but all the people to whose attention this festival came; and the same was done in the calpulcos and on all the teocaltin. All prayed, and besought of Tezcatlipoca that he grant them favors, for it was thought that he was almighty.|
|1-Quiauitl||1-Quiauitl||They celebrated a feast to the Cihuapipilti, the women who died during childbirth. They said that they became teteo and that they dwelt in the house of the sun; and that when this sign reigned, they came down to the earth and afflicted with various sicknesses those whom they met outside of their houses. And hence, in these days, they dared not go out of their houses. They had shrines built in honor of these teteo in all the suburbs where two streets crossed, which they called cihuateocalli, or by another name, cihuateopan. In these shrines they had the images of the Cihuapipilti, and on these days they adorned them with papers which they called amateteuitl. On this feast they slew in their honor those condemned to death for some crime, who were in the jails.|
|4-Ehecatl||1-Quiauitl||Because this house was very unlucky they slew in it the malefactors who were imprisoned. And likewise the lord had a number of slaves slain as a superstition. And the merchants and traders made a show or demonstration of the jewels in which they dealt, bringing them forth so that all might see them. And afterwards, at night, they ate and drank, and held flowers and those canes of perfume. And they sat in their seats boasting of what they had gained and of the distant parts which they had reached while mocking the others for their counting for little.|
|2-Acatl||1-Malinalli||They celebrated a great festival for Tezcatipoca and fashioned an image of Omacatl which was taken to the house of the one who felt devotion that it might bless him and cause his goods to increase. He who would let this image go, waited until the next time when the same sign reigned. Then he returned it whence he had taken it.|
|1-Tecpatl||1-Tecpatl||They brought forth all the ornaments of Huitzilopochtli and they put them in the sun. They said that this was his sign and that of Camaxtli. This they did at Tlacatecco. Here they set out, on this day, many kinds of food, very well cooked, like that which the lords eat. They presented all of them before his image. After they had remained there a while, the officials of Huitzilopochtli took them up and divided them among themselves, and ate them. And they also incensed the image and offered it quail. They struck off their heads before it, so the blood should be shed before the image. And the lord offered all the precious flowers which the lords used, before the image.|
|1-Ozomahtli||1-Ozomahtli||They said that the Cihuapipilti came down to the earth and they harmed the boys and girls, afflicting them with palsy. And if anyone, at this time, sickened, they said that the Cihuapipilti had caused it; that he had come upon them. And the fathers and mothers on these days did not let their children go outside the houses, so that they might not come upon these Cihuapipilti, whom they held in great dread.|
|1-Itzcuintli||1-Itzcuintli||They held a great festival in honor of Xiutecuhtli because they said this was the sign of fire. In it they offered him much copalli and many quail. They arrayed his image in many kinds of papers with rich adornments. Among the rich and powerful, they celebrated a great feast in honor of the fire, in their own houses; they held dinners and banquets in honor of the fire. In this same sign they held elections of lords and consuls, and in the fourth house of this sign they enacted the formalities of their elections, feasts, dances, and gift-giving. After these feasts, they forthwith proclaimed war against their foes.|
|1-Atl||1-Atl||All those who dealt in water celebrated a festival - those who sold water, as well as those who fished, and those who gained other livelihoods which there are in the water- to Chalchiuhtlicue. These arrayed her image and laid offerings before her, and revered her in the house called calpulli.|
|Various||Various||Whenever a child was bathed there was an accompanying feast. The parents took great care in documenting the sign, the day, and the hour in which the child was born and sought the advice of the tonalpoque to ask as to the good fortune or ill of the child who was born. And if the sign in which the child was born was propitious, they had him bathed at once; and if it was adverse they sought the most favorable house of that sign in which to bathe him. When they bathed him, they banqueted the kinsmen and friends, so that they would be present at the bathing, and then they gave food and drink to all the guests, and also to the children of the whole suburb. The midwife bathed the child at sunrise in the house of his father while uttering many prayers and performing much ceremony over the child.|
|Various||Various||After the marriage ceremony there was dining, and drinking, and dances, which were given thereafter, as is contained in the account of the marriages.|
Teteo Day Number Assignments
|9||Quetzalcoatl or Ehecatl||Turkey|
|11||Chalmecatl or Mictlantecuhtli||Macaw|
Teteo Day Sign Assignment
|15||Eagle||Cuauhtli||Red Tezcatlipoca or Xipe Totec|
- Nahuatl-English English-Nahuatl, Fermin Herrera, page 196.
- Sahagun, Bernardino. Florentine Codex, book 2. Pages 35-41
- Boone, Elizabeth Hill. Cycles of Time and Meaning in the Mexican Books of Fate. page 46
- Boone, Elizabeth Hill. Cycles of Time and Meaning in the Mexican Books of Fate. page 47