Principal English Translation: 

the place where something occurs or is habitually done (see Karttunen); a locative

Frances Karttunen: 

-YĀN place where something is habitually done / el lugar y a veces el tiempo donde uno ejercita la accion del verbo (C) This suffixed element occurs in many set constructions with extended senses of place and duration. C analyzes it into sufflixal –N added to deverbal instrumental nouns ending in –YA (f.50r). These nouns are otherwise identical in form with imperfects, and this in turn suggests that the imperfect suffix is –YĀ with a long vowel, although the vowel is shortened in the singular imperfect by virtue of being word-final and in the plural because it precedes a glottal stop.
Frances Karttunen, An Analytical Dictionary of Nahuatl (Norman: University of Oklahoma Press, 1992), 335.

Attestations from sources in English: 

teilpiloyan = te (impersonal object) + ilpia (to tie up or put in jail) + lo (passive) + yan (place of habitual action) = prison, or the place where people are tied up
Rebecca Horn's notes from Nahuatl classes with James Lockhart. Card file in possession of Stephanie Wood.