yohuac.

Headword: 
yohuac.
Principal English Translation: 

at night, pertaining to the night; or very early in the morning
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), 242.

Orthographic Variants: 
youac, yoac, yuuac, yuhuac
IPAspelling: 
yowɑk
Alonso de Molina: 

youac. de noche.
Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1571, part 2, Nahuatl to Spanish, f. 41v. col. 1. Thanks to Joe Campbell for providing the transcription.

yoac. de noche. aduerbio.
Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1571, part 2, Nahuatl to Spanish, f. 39v. col. 1. Thanks to Joe Campbell for providing the transcription.

yuuac. de noche.
Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1571, part 2, Nahuatl to Spanish, f. 44r. col. 2. Thanks to Joe Campbell for providing the transcription.

yuuac niquiza. (pret. yuuac oniquiz.) madrugar.
Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1571, part 2, Nahuatl to Spanish, f. 44r. col. 2. Thanks to Joe Campbell for providing the transcription.

yuuac nineua. (pret. yuuac onineuh.) madrugar.
Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1571, part 2, Nahuatl to Spanish, f. 44r. col. 2. Thanks to Joe Campbell for providing the transcription.

Frances Karttunen: 

YOHUAC at night / de noche (M) See YOHUA.
Frances Karttunen, An Analytical Dictionary of Nahuatl (Norman: University of Oklahoma Press, 1992), 340.

Horacio Carochi / English: 

yohuac = at night or very early in the morning
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), 516, and see 356-67, 388-89.

Andrés de Olmos: 

Youac, noche, o de noche.
Andrés de Olmos, Arte para aprender la lengua Mexicana, ed. Rémi Siméon, facsimile edition ed. Miguel León-Portilla (Guadalajara: Edmundo Aviña Levy, 1972), 189.

Lockhart’s Nahuatl as Written: 

particle. from yohua?
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), 242.

Attestations from sources in English: 

auh yn iquac ye achi yohuac yn ichantzinco. yn sancta ma = and when it had gotten a bit darker in Saint Mary’s house (early seventeenth century, Central Mexico)
Louise M. Burkhart, Before Guadalupe: The Virgin Mary in Early Colonial Nahuatl Literature, Institute for Mesoamerican Studies Monograph 13 (Albany: University at Albany, 2001), 105.

auh yn iquac ye yohuac yn ye motecaz = and when it was dark, when she was about to lie down (early seventeenth century, Central Mexico)
Louise M. Burkhart, Before Guadalupe: The Virgin Mary in Early Colonial Nahuatl Literature, Institute for Mesoamerican Studies Monograph 13 (Albany: University at Albany, 2001), 142.

Attestations from sources in Spanish: 

ye yohuac ye cotoca 8 oras = ya en la noche, corrían las ocho horas (Tlaxcala, 1662–1692)
Juan Buenaventura Zapata y Mendoza, Historia cronológica de la Noble Ciudad de Tlaxcala, transcripción paleográfica, traducción, presentación y notas por Luis Reyes García y Andrea Martínez Baracs (Tlaxcala y México: Universidad Autónoma de Tlaxcala, Secretaría de Extensión Universitaria y Difusión Cultural, y Centro de Investigaciones y Estudios Superiores en Antropología Social, 1995), 392–393.

themes: 
Time, Calendar, Frequency