an abyss (see Molina); this would also appear to have water and cave associations (SW)
Alonso de Molina:
abismo. S. agua profunda. aoztoc. amixtlan. auecatlan. axoxouilli. Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1555, part 1, Spanish to Nahuatl, f. 1v.