a slanted bell (see Molina; partly a loanword from Spanish, campana, bell)
Alonso de Molina:
piaztic campana. campana esquilonada. Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1571, part 2, Nahuatl to Spanish, f. 81v. col. 1. Thanks to Joe Campbell for providing the transcription.