the stone or pit from a piece of fruit (see Molina and Karttunen)
IPAspelling:
piːtstɬi
Alonso de Molina:
pitztli. cuexco o huesso de cierta fruta. Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1571, part 2, Nahuatl to Spanish, f. 82v. col. 1. Thanks to Joe Campbell for providing the transcription.
Frances Karttunen:
PĪTZ-TLI pit, stone of a fruit / cuesco o hueso de cierta fruta (M) [(1)Tp.127]. Frances Karttunen, An Analytical Dictionary of Nahuatl (Norman: University of Oklahoma Press, 1992), 199.