ocuilin.

Headword: 
ocuilin.
Principal English Translation: 

a worm
James Lockhart, Nahuatl as Written: Lessons in Older Written Nahuatl, with Copious Examples and Texts (Stanford: Stanford University Press and UCLA Latin American Studies, 2001), 228.

Orthographic Variants: 
ucuilin
Alonso de Molina: 

ocuilin. gusano, generalmente, o ceuo para pescar.
Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1571, part 2, Nahuatl to Spanish, f. 76r. col. 1. Thanks to Joe Campbell for providing the transcription.

Frances Karttunen: 

OCUIL-IN pl: -TIN worm, caterpillar / gusano generalmente, o cebo para pescar (M) Z also uses OCUIL-IN with the sense ‘wild animal'.
Frances Karttunen, An Analytical Dictionary of Nahuatl (Norman: University of Oklahoma Press, 1992), 176.

Attestations from sources in English: 

vcuil = Worm, a name given to a child
Fray Bernardino de Sahagún, Primeros Memoriales, ed. Thelma D. Sullivan, et al. (Norman: University of Oklahoma Press, 1997), 254.

in tlahtlacolocuilin, in Mictlanocuilin = the worm of sin, the worm of the place of the dead (late sixteenth century, Central Mexico)
Louise M. Burkhart, Before Guadalupe: The Virgin Mary in Early Colonial Nahuatl Literature, Institute for Mesoamerican Studies Monograph 13 (Albany: University at Albany, 2001), 18.