a calendar; literally, a day-count book (see Molina)
Orthographic Variants:
ilhuitlapoal amoxtli
Alonso de Molina:
ilhuitlapoal amoxtli. calendario. Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1571, part 2, Nahuatl to Spanish, f. 37v. col. 1. Thanks to Joe Campbell for providing the transcription.