Tepeilhuitl.

Headword: 
Tepeilhuitl.
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), 178.

Attestations from sources in English: 

This was the festival of the hills or mountains, the thirteenth festival of the year. The ceremonies of this festival were dedicated to Tlaloc, principal rain deity, and other mountains associated with the tlaloque (other rain deities).
Bernardo Ortiz de Montellano, "Las hierbas de Tláloc," Estudios de cultura náhuatl 14 (1980), 287–314, see p. 292.