acatl.

See an image that represents acatl in the Visual Lexicon of Aztec Hieroglyphs, ed. Stephanie Wood (Eugene, Ore.: Wired Humanities, 2020-present).

acaxihuitl (also, acaxiuitl, and acaxivitli) = Reed year
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), 168–169, 174–175.

mochantzinco. yn toltzallan. yn acatzallan = your home among the sedges and the reeds. (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. 1, 116–117.

auh ca nel tetlalpan yn cate yn motlallico yn tollitic yn acayhtic = And really they were on [other] people's land when they settled in the sedges and reeds. (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. 1, 104–105.

yn toltzallan yn acatzallan = among the sedges and the reeds (a metaphor for Mexico Tenochtitlan)
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. 1, 116–117.

ipan xii. acatl xihuitl. 1705 años = in the year 12 Reed, 1075 (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), 118–119.

A calendrical marker. For example: ce acatl, 1 acatl = el año 1519, entre otros. (central Mexico, sixteenth century)
Luis Reyes García, ¿Como te confundes? ¿Acaso no somos conquistados? Anales de Juan Bautista [1563–1574] (Mexico: Centro de Investigaciones y Estudios Superiores en Antropología Social, Biblioteca Lorenzo Boturini Insigne y Nacional Basílica de Guadalupe, 2001), 133.

Other examples:
5 acatl = 1523;
9 acatl = 1527. (central Mexico, sixteenth century)
Luis Reyes García, ¿Como te confundes? ¿Acaso no somos conquistados? Anales de Juan Bautista [1563–1574] (Mexico: Centro de Investigaciones y Estudios Superiores en Antropología Social, Biblioteca Lorenzo Boturini Insigne y Nacional Basílica de Guadalupe, 2001), 133.

Good days for getting married were acatl, ozomatli, cipactli, quauhtli, and calli, according to the Florentine Codex. (central Mexico, sixteenth century)Hubert Howe Bancroft, The Native Races of the Pacific States of North America, Vol. II, Civilized Nations (London: Longmans, Green, and Co., 1875), 255.

tacaio = our reed (central Mexico, sixteenth century)
Fr. Bernardino de Sahagún, Florentine Codex: General History of the Things of New Spain; Book 10 -- The People, No. 14, Part 11, 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), 132.

Qujl in qualli tonalli: iehoatl in acatl, oҫumatli, cipactli, quauhtli, calli = They said the good days were Reed, Monkey, Crocodile, Eagle, House (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), 129.

ynic umeti ytoca acatl ya nauhxivitl = The second is named Acatl, born four years ago (Cuernavaca region, ca. 1540s)
The Book of Tributes: Early Sixteenth-Century Nahuatl Censuses from Morelos, ed. and transl. S. L. Cline, (Los Angeles: UCLA Latin American Center Publications, 1993), 170–171.

Toribio Hacat was the head of a household of two people, as reported in the Códice de Santa María de la Asunción of Tepetlaoztoc (Tetzcoco).
Barbara J. Williams, "Mexico: Aztec Soil Classification and Land Tenure," Actes de XLIIe Congrès International des Américanistes, 9 (Paris: Société des Américanistes, 1980), pp. 165–175. See p. 171.

au ipanpa cemicac tlaneltilities omo tlilmachioti axcan ipan nahui cali tecpatl cali tochi acatl cen chiquipil molpia ipan cas tolpuali ihuan matlacpuali yhuan epuali ihua chique chihuitl cahuitl = Pues para siempre estar dando testimonio de este hecho, se escribió y firmó ahora en este dia cuatro casa. Pedernal, Casa, Consejo, Caña, (4 trecenas) en un atado de años se atan. Encima de quinientos sesenta y ocho años el tiempo. (Estado de Hidalgo, ca. 1722?)
Rocío Cortés, El "nahuatlato Alvarado" y el Tlalamatl Huauhquilpan: Mecanismos de la memoria colectiva de una comunidad indígena (New York: Hispanic Seminary of Medieval Studies, Colonial Spanish American Series, 2011), 30–31, 42.
Nica toxiuhal 10 acatl, hamdres cipac alguacil = Aquí, nuestro año 10 acatl. Andrés Cipac, alguacil. (Tetzcoco, 1587)
Benjamin Daniel Johnson, “Transcripción de los documentos Nahuas de Tezcoco en los Papeles de la Embajada Americana resguardados en el Archivo Histórico de la Biblioteca Nacional de Antropología e Historia de México”, en Documentos nahuas de Tezcoco, Vol. 1, ed. Javier Eduardo Ramírez López (Texcoco: Diócesis de Texcoco, 2018), 126–127.