maza cacti.

Headword: 
maza cacti.
Principal English Translation: 

the person who brands horses or large animals (see Molina)

Alonso de Molina: 

maza cacti. herrador de bestias.
Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1571, part 2, Nahuatl to Spanish, f. 50r. col. 1. Thanks to Joe Campbell for providing the transcription.

Attestations from sources in English: 

The use of "maza" for horse appears to date to the early days following the Spanish invasion of Mexico, when the Nahuas had not yet learned the loanword caballo and therefore used the term mazatl (deer). (SW)