mo-.

Headword: 
mo-.
Principal English Translation: 

pronominal prefix of a reflexive verb, third-person singular and plural

Lockhart’s Nahuatl as Written: 

reflexive prefix for all the persons except the first and for both numbers.
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), 255.