cozamalotl.

Headword: 
cozamalotl.
Principal English Translation: 

a rainbow (see Molina and Karttunen)

Orthographic Variants: 
coçamalutl, aiauhcoçamalotl, yuauhcoçamalotl, ayauh cozamalotl, ayauhcozamalotl
IPAspelling: 
koːsɑmɑːloːtɬ
Alonso de Molina: 

cozamalotl. arco del cielo.
Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1571, part 2, Nahuatl to Spanish, f. 23r. col. 1. Thanks to Joe Campbell for providing the transcription.

Frances Karttunen: 

CŌZAMĀLŌ-TL rainbow / arco del cielo (M), arco iris (S)
Frances Karttunen, An Analytical Dictionary of Nahuatl (Norman: University of Oklahoma Press, 1992), 43.

Attestations from sources in English: 

yquac ylhuicatitech hualmonexti yuauhcoçamalotl quiyahuallotimoma in tonatiuh yhua ce quixnamic auh in tonatiuh ça tlacaltechpan yetiuh onpa yquiçayanpa yetihuitz auh yn tiquittaqueue aço ye chiuhcnahui hora auh mochitlacatl quittac yn titehuan yhuan españolesme auh yn mocahuato ye nepantla tonatiuh valmocruztecac yn tlanepantla. = in the sky there appeared a misty rainbow, which surrounded the sun as it rose; and another rose opposite the sun during the morning. We saw this after nine o’clock. Everyone saw it: we and the Spanish. By midday they came together in the middle [of the sky], the sun, in the shape of a cross in the middle
Ezequiel G. Stear, Nahua Horizons: Writing, Persuasion, and Futurities in Colonial Mexico (Tucson: University of Arizona Press, 2025), 141, citing Anales de Juan Bautista, 1582, f. 56v.

Auh ynic mocuep onpa ytztia tlatatacco yhuan çan no onpa polihuito yn icpac tlaltepehualli yn ehecatl yhua ynic quittaque yuhqui yn itlahitic ycatia hehecatl. Auh yn iquac yauhcoçamalotl monexti ylhuicatitech quitoqueyn espanolesme aço ye tlamiz in cemanauac auh cequintin quitoque aço timayanzque anoço yaoyotl topan mochivaz anoço cana ye neci yancuic tlalli, etc. (ADJB, f. 56v–57r) = Coming back, [the whirlwind] came to the place where the hole was made in the ground, and there the wind dissipated over the mound of dirt. They saw that inside of the hole, there stood Ehecatl. When the misty rainbow appeared in the sky, the Spanish said that perhaps the world was coming to an end. Others said that perhaps a famine was coming, or war was upon us, or that somewhere new earth was appearing, etc.
Ezequiel G. Stear, Nahua Horizons: Writing, Persuasion, and Futurities in Colonial Mexico (Tucson: University of Arizona Press, 2025), 144–145, citing Anales de Juan Bautista, 1582, f. 56v–57r.

ayauh cozamalotl (noun) = the rainbow; lit., "mist of water jewels" Daniel Garrison Brinton, Ancient Nahuatl Poetry: Containing the Nahuatl Text of XXVII Ancient Mexican Poems (1887), 150.

See a drawing and a painting of rainbows (represented in the text as aiauhcoçamalotl) in Book 7, f. 12r of the Florentine Codex. These are published on line in Digital Florentine Codex. https://florentinecodex.getty.edu/book/7/folio/12r/images/0a039a7c-e265-....