head stone, a stone for a burial (see Molina); the implication is that it has writing carved on it and it is related to a death
Alonso de Molina:
micca tetlacuilolli. piedra de sepultura. Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1571, part 2, Nahuatl to Spanish, f. 56r. col. 1. Thanks to Joe Campbell for providing the transcription.