Tozoztontli.

Headword: 
Tozoztontli.
Principal English Translation: 

the name of a month of twenty days

James Lockhart, We People Here: Nahuatl Accounts of the Conquest of Mexico, Repertorium Columbianum v. 1 (Los Angeles: UCLA Center for Medieval and Renaissance Studies, 1993), 174, 178.

Orthographic Variants: 
Toçoztontli
Attestations from sources in English: 

8 Abril. Toçoztontli = 8 April. Tozoztontli. (central Mexico, early seventeenth century)
Codex Chimalpahin: Society and Politics in Mexico Tenochtitlan, Tlatelolco, Culhuacan, and Other Nahuatl Altepetl in Central Mexico; The Nahuatl and Spanish Annals and Accounts Collected and Recorded by don Domingo de San Antón Muñón Chimalpahin Quauhtlehuanitzin, eds. and transl. Arthur J. O. Anderson and Susan Schroeder (Norman: University of Oklahoma Press, 1997), vol. 2, 120–121.

This was the third festival of the year. It involve a small vigil. It was dedicated to Tlaloc and the deities of maize. The herbs iztauhyatl and yauhtli were a part of the ceremonies.
Bernardo Ortiz de Montellano, "Las hierbas de Tláloc," Estudios de cultura náhuatl 14 (1980), 287–314, see p. 291.