huiptla.

Headword: 
huiptla.
Principal English Translation: 

the day after tomorrow or the day before yesterday (the latter, especially when seen as ye huiptla); mostly, this is forward looking

Orthographic Variants: 
huictla, huitla, uiptla
IPAspelling: 
wiːptɬɑ
Alonso de Molina: 

uiptla. despues de mañana.
Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1571, part 2, Nahuatl to Spanish, f. 157v. col. 2. Thanks to Joe Campbell for providing the transcription.

Frances Karttunen: 

HUĪPTLA day after tomorrow / después de mañana (M) This often appears in the phase MŌZTLA HUĪPTLA ‘in the future,’ literally ‘tomorrow, day after tomorrow’. HUĪCTLA See HUĪPTLA.
Frances Karttunen, An Analytical Dictionary of Nahuatl (Norman: University of Oklahoma Press, 1992), 90.

Horacio Carochi / English: 

huīptla = the day after tomorrow or the day before yesterday
Horacio Carochi, S.J., Grammar of the Mexican language with an explanation of its adverbs (1645), translated and edited with commentary by James Lockhart, UCLA Latin American Studies Volume 89 (Stanford: Stanford University Press, UCLA Latin American Center Publications, 2001), 502.

Lockhart’s Nahuatl as Written: 

particle. ye huīptla, the day before yesterday. mōztla huīptla, in the future. 218
James Lockhart, Nahuatl as Written: Lessons in Older Written Nahuatl, with Copious Examples and Texts (Stanford: Stanford University Press and UCLA Latin American Studies, 2001), 218.

Attestations from sources in English: 

mostla huictla = it in the future (Santa María de la Asunción, Toluca Valley, 1760)
Caterina Pizzigoni, ed., Testaments of Toluca (Stanford: Stanford University Press and UCLA Latin American Center Publications, 2007), 183.

In the Valley of Toluca, one can find huictla and huitla, since syllable-final p is rare in Nahuatl.
Caterina Pizzigoni, ed., Testaments of Toluca (Stanford: Stanford University Press and UCLA Latin American Center Publications, 2007), 37.

In muztla, in uiptla. Quitoznequi: in ye ompa titztiui, in za(n) quezquilhuitl. = Tomorrow, the day after tomorrow. This means: We shall be seeing each other in just a few days.
Thelma D. Sullivan, "Nahuatl Proverbs, Conundrums, and Metaphors, Collected by Sahagún," Estudios de Cultura Náhuatl 4 (1963), 140–141.

ma tictochialilican in quen muztla, viptla = let us await how it will be in a day, in two days (central Mexico, sixteenth century)
Fr. Bernardino de Sahagún, Florentine Codex: General History of the Things of New Spain; Book 6 -- Rhetoric and Moral Philosophy, No. 14, Part 7, eds. and transl. Arthur J. O. Anderson and Charles E. Dibble (Santa Fe and Salt Lake City: School of American Research and the University of Utah, 1961), 186.

Attestations from sources in Spanish: 

jueves huiptla jueves = Pasado mañana jueves (Quauhtinchan, s. XVI)
Historia Tolteca-Chichimeca, eds. Paul Kirchhoff, Lina Odena Güemes, y Luis Reyes García (México: CISINAH, INAH-SEP, 1976), 131.