citlalin.

Headword: 
citlalin.
Principal English Translation: 

star(s); when combined with popoca, a comet; when combined with huei, the planet Venus
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), 215.

the appearance of the morning star also relates to the time of day, with dawn

Orthographic Variants: 
citlalli, sitlanlli, citlali
IPAspelling: 
sitɬɑːlli
Alonso de Molina: 

citlalin. estrella.
Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1571, part 2, Nahuatl to Spanish, f. 22v. col. 1. Thanks to Joe Campbell for providing the transcription.

Frances Karttunen: 

CĪTLAL-IN pl: CĪCĪTLALTIN star / estrella (M)
Frances Karttunen, An Analytical Dictionary of Nahuatl (Norman: University of Oklahoma Press, 1992), 35.

Lockhart’s Nahuatl as Written: 

citlalin = star
abs. pl. cīcītlaltin. huēi cītlalin, the planet Venus. with popōca, a comet.
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), 215.

Attestations from sources in English: 

in huel tehuatzin tiquinmochichihuili tiquinmoqualnextili. yn ilhuicame. yn inca in cicitlaltin yn ica in tonatiuh. yn ica yn metztli = You Yourself Who adorned and embellished the heavens with the stars, the sun, and the moon (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, 140–141.

yquac mochi tlacatl oquittac ce citlalli popocaya ohualnez ylhuicatitech ye nipa hualitztia mictlampa y norte yhuicpa yn azcapotzalcopa = when everyone saw a comet that appeared in the sky it headed this way from off to the north, from toward Azcapotzalco (Mexico City, 1600–1630)
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), 201.

mochi tlacatl. oquittac. ce citlalli popocaya = everyone saw a comet (early seventeenth century, central New Spain)
Annals of His Time: Don Domingo de San Antón Muñón Chimalpahin Quauhtlehuanitzin, James Lockhart, Susan Schroeder, and Doris Namala, eds. and transl. (Stanford: Stanford University Press, 2006), 102–103.

1620 Nican ypa xihuitl yn sitlalin ypan ylhuitzin san diego = 1620 Here in this year a comet appeared on the feast day of San Diego. (Tlaxcala-Puebla, seventeenth century)
Here in This Year: Seventeenth-Century Nahuatl Annals of the Tlaxcala-Puebla Valley, ed. and transl. Camilla Townsend, with an essay by James Lockhart (Stanford: Stanford University Press, 2010), 90–91.

citlalmaololo = handful of stars (central Mexico, sixteenth century)
Fr. Bernardino de Sahagún, Florentine Codex: General History of the Things of New Spain; Book 2 -- The Ceremonies, no. 14, Part III, 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, 1951), 64.

cicitlaltin = stars (central Mexico, sixteenth century)
Louise M. Burkhart, Before Guadalupe: The Virgin Mary in Early Colonial Nahuatl Literature, Institute for Mesoamerican Studies Monograph 13 (Albany: University at Albany, 2001), 109.

motenehua limpia concepcion yn itech pohui ye in tonatiuh. in Metztli. yn huey citlalli tlathuinahuac hualquiҫa. in tlatzacuilotl tzauhctiuh, yn iteocaltzin tto. dios. ynic ahuaztli ylhuicac. in ҫoyatl. yn azetonasquahuitl. yn ahuehuetl, yn tlatzca. yn tezcatl. yn castillan tulpatlachuitztecolxochitl lilio. yn xuchitl Rosa = called the Immaculate Conception, to which belong the sun, the moon, and the great star that comes out close to dawn [Venus], when the gate of our lord God's temple is closing, as a ladder to heaven; the palm tree; the olive tree; the cypress; the mirror; the Spanish flower from a broad-leafed water plant, the lily; the rose (central Mexico, 1613)
Annals of His Time: Don Domingo de San Antón Muñón Chimalpahin Quauhtlehuanitzin, James Lockhart, Susan Schroeder, and Doris Namala, eds. and transl. (Stanford: Stanford University Press, 2006), 246–7.

Attestations from sources in Spanish: 

1691 años ocualoc tonali... yn otlayohua nesque sisitlantin tzatzique caxtilme yhuan totome auh yn ochipahuac tonali huel ypa chi[cu]naui hora = 1691, se eclipsó el sol... se obscureció, aparecieron las estrellas, gritaron los gallos y los pájaros. El sol se limpió a las nueve 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), 642–643.

opeuhqui çitlali popoca çanoyapa quitecaya yn iuhqui icuitlapil = empezó a humear la estrella, por todas partes del cielo aparecía lo que parecía su cola (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), 344-345.