a small white marine shell (see Molina), or a snail shell (see Olko, entry for chipolcozcatl)
Orthographic Variants:
chipuli, chipulli, chipoli
Alonso de Molina:
chipuli. caracol. Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1571, part 2, Nahuatl to Spanish, f. 21r. col. 2. Thanks to Joe Campbell for providing the transcription.