momecatiliztli.

Headword: 
momecatiliztli.
Principal English Translation: 

concubinage (literally, "tying oneself" to someone)
momecatiliztli, literally, "tying oneself" to someone).

Louise M. Burkhart, Before Guadalupe: The Virgin Mary in Early Colonial Nahuatl Literature, Institute for Mesoamerican Studies Monograph 13 (Albany: University at Albany, 2001), 50.