to cook something in a pot, or to make something boil, or to bring up froth or foam (see Molina)
IPAspelling:
posoːniɑː
Alonso de Molina:
pozonia. nitla. (pret. onitlapozoni.) cozer algo en olla, o caldera, o hazer heruir alguna cosa, o hazer espuma. Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1571, part 2, Nahuatl to Spanish, f. 83r. col. 1. Thanks to Joe Campbell for providing the transcription.
Frances Karttunen:
POZŌNIĀ vt to boil something / lo hierve (T) [(6)Tp.198,(3)Xp.73]. See POZŌN(I).
POZŌNILIĀ applic. POZŌNIĀ.
POZŌNĪLŌ nonact. POZŌNIĀ. Frances Karttunen, An Analytical Dictionary of Nahuatl (Norman: University of Oklahoma Press, 1992), 205.