he who seals (locks, closes) a letter or a piece of writing (see Molina)
Orthographic Variants:
amatlacuiloltzaquani
Alonso de Molina:
amatlacuiloltzaquani. el que cierra carta o escriptura. Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1571, part 2, Nahuatl to Spanish, f. 4v. col. 2. Thanks to Joe Campbell for providing the transcription.