ayahuitl.

Headword: 
ayahuitl.
Principal English Translation: 

cloud, fog, mist (see Karttunen); fog; or, a cloudiness in the eye (see Molina)

Orthographic Variants: 
āyahuitl, ayauitl
IPAspelling: 
ɑːyɑwitɬ
Alonso de Molina: 

ayauitl. niebla, neblina, o nuue del ojo.
Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1571, part 2, Nahuatl to Spanish, f. 3r. col. 2. Thanks to Joe Campbell for providing the transcription.

Frances Karttunen: 

ĀYAHU(I)-TL cloud, fog / niebla, neblina, o nube del ojo (M) This has an interesting similarity to QUIYAHU(I)-TL rainstorm. See Ā-TL.
Frances Karttunen, An Analytical Dictionary of Nahuatl (Norman: University of Oklahoma Press, 1992), 16.

Attestations from sources in English: 

ayahuitl (noun) = fog, mist, vapor
Daniel Garrison Brinton, Ancient Nahuatl Poetry: Containing the Nahuatl Text of XXVII Ancient Mexican Poems (1887), 150.

in ipocyo, in ayauhyo: quitoznequi: imauizo, itenyo: anozo aca ueca oya, ayamo poliui in itenyo, in imauizzo = smoke and mist, meaning his fame and glory, had not yet vanished; or, about someone who had gone far away and whose fame and glory had not faded Thelma D. Sullivan, "Nahuatl Proverbs, Conundrums, and Metaphors, Collected by Sahagún," Estudios de Cultura Náhuatl 4 (1963), 144–145.

themes: 
Health, Sickness, Wellness, Medicine
Weather, Climate