Principal English Translation: 

rare verbal prefix indicating the plurality of the direct obj. when the full obj. prefix refers to the indirect object

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), 220.

Lockhart’s Nahuatl as Written: 

-in- form taken by -im- if a nonlabial consonant follows. 220