coyahuac.

Headword: 
coyahuac.
Principal English Translation: 

wide; broad; enlarged; open, like a window (see Molina and attestations)

Orthographic Variants: 
coyauac, coyaoac, coiaoac
IPAspelling: 
koyɑːwɑk
Alonso de Molina: 

coyauac. cosa ancha, assi como caño de agua, o ventana. &c.
Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1571, part 2, Nahuatl to Spanish, f. 24r. col. 1. Thanks to Joe Campbell for providing the transcription.

Frances Karttunen: 

COYĀHUAC something wide / cosa ancha, así como caño de agua o ventana, etc. (M) See COYĀHU(A).
Frances Karttunen, An Analytical Dictionary of Nahuatl (Norman: University of Oklahoma Press, 1992), 42.

Attestations from sources in English: 

Molina points to the use of this term to describe the width of a water canal or a window, but it is seen in mid-sixteenth-century Coyoacan to describe the width of parcels of land. In late sixteenth-century Tlaxcala, we also see coyahuatiuh for the width of a parcel.

coyahuac = wide; some number in width (similar to patlahuac, though less frequently seen)
Rebecca Horn, Postconquest Coyoacan: Nahua-Spanish Relations in Central Mexico, 1519-1650 (Stanford: Stanford University Press, 1997), 153.

epovalcoyavac napovalviyac = 60 wind, 80 long (Coyoacan, mid-sixteenth c.)
Beyond the Codices, eds. Arthur J.O. Anderson, Frances Berdan, and James Lockhart (Los Angeles: UCLA Latin American Center, 1976), Doc. 18, 110–111.

In tlauilli, in ocotl, in machiotl, in octacatl, in coyaoac tezcatl: mixpan nicmana. Inin tlatolli iechpa mitoaya: in aquin tecutlatoaya, in iuicpa maceoalli, in cenca qualli tlatolli iixpan = I set before you a light, a torch, a model, a measuring rod, a great mirror. This phrase was said of a lord who spoke to the people and placed before them excellent words.
Thelma D. Sullivan, "Nahuatl Proverbs, Conundrums, and Metaphors, Collected by Sahagún," Estudios de Cultura Náhuatl 4 (1963), 150–151.

coiaoac = wide (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.

Attestations from sources in Spanish: 

chiquacenpoual nehuitzanali napoual coyauatiuh = ciento veinte brazas del pie a la mano y de ancho ochenta
Vidas y bienes olvidados: Testamentos indígenas novohispanos, vol. 1, Testamentos en castellano del siglo XVI y en náhuatl y castellano de Ocotelulco de los siglos XVI y XVII, eds. Teresa Rojas Rabiela, Elsa Leticia Rea López, y Constantino Medina Lima (Santa Bárbara, Tamascolco, Tlaxcala, 1598), 290–291.

themes: 
Measurements, Quantities