ixtlahuatl.

Headword: 
ixtlahuatl.
Principal English Translation: 

a flat plain, savanna, or countryside (see Molina and Karttunen)

Orthographic Variants: 
yxtlahuatl, ixtlauatl
IPAspelling: 
iʃtɬɑːwɑtɬ
Alonso de Molina: 

ixtlauatl. vega o tierra llana, zauana, o campo.
Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1571, part 2, Nahuatl to Spanish, f. 48v. col. 1. Thanks to Joe Campbell for providing the transcription.

Frances Karttunen: 

IXTLĀHUA-TL plain, field, savanna / vega o tierra llana, sabana (M) [(2)Bf.4v,7r, (6)Zp.78,95,101,164]. Z has a long initial vowel, but B specifically marks it short
Frances Karttunen, An Analytical Dictionary of Nahuatl (Norman: University of Oklahoma Press, 1992), 121.

Attestations from sources in English: 

in tipilhuan Eua, mohuiccopatzinco tonelçiçiuhtinemi tichocatinemi in nican choquizixtlahuacan = we the children of Eve cry out to you, here in the desert of weeping we go about sighing, crying out towards you
Bartolomé de Alva, A Guide to Confession Large and Small in the Mexican Language, 1634, eds. Barry D. Sell and John Frederick Schwaller, with Lu Ann Homza (Norman: University of Oklahoma Press, 1999), 163.

ixtlahuatl = open field, savanna, desert
Daniel Garrison Brinton, Ancient Nahuatl Poetry: Containing the Nahuatl Text of XXVII Ancient Mexican Poems (1887), 156.

There is a difrasismo,"in ixtlahuatl, in teotlalli," "la llanura, la tierra divina," which seems related to living a healthy life. It is contrasted with living in caves in the mountains. (sixteenth century, Quauhtinchan)
Historia Tolteca-Chichimeca, eds. Paul Kirchhoff, Lina Odena Güemes, y Luis Reyes García (México: CISINAH, INAH-SEP, 1976), 167.

Attestations from sources in Spanish: 

nocal nican altepe ytec nican mani ycanpatzinco calnacazco yxtlahuatl ypan ytzticac yn caltentli yn centle tonatiuh yquiçayanpa ytzticac = mi casa que tengo está dentro de el pueblo, en el llano pegada a la esquin[a] de la loma, que la una puerta mira hacia el oriente (Zempoala, "1610", but probably Techialoyan -related)
Vidas y bienes olvidados: Testamentos en náhuatl y castellano del siglo XVII, vol. 3, Teresa Rojas Rabiela, et al, eds. (México: CIESAS, 2002), 76–77.

yxtlahuatl = llanura
Xavier Noguez, Códice Techialoyan de San Pedro Tototepec (Estado de México), México, El Colegio Mexiquense A.C. y Gobierno del Estado de México, 1999), 37.

themes: 
Landscape Features