pocyotl.

amo pocyo yez yn quavitl = the wood will not be smoky (Central Mexico, 1552)
Fray Alonso de Molina, Nahua Confraternities in Early Colonial Mexico: The 1552 Nahuatl Ordinances of fray Alonso de Molina, OFM, ed. and trans., Barry D. Sell (Berkeley: Academy of American Franciscan History, 2002), 128–129.

Sãno ypan xihuitl yn opopcac sitlalin ypan cuaresma ypan marso yn ipocyo tlacpacpa ytztoya = In this same year a comet appeared during Lent, in March. Its tail faced upward.
Here in This Year: Seventeenth-Century Nahuatl Annals of the Tlaxcala-Puebla Valley, ed. and transl. Camilla Townsend, with an essay by James Lockhart (Stanford: Stanford University Press, 2010), 106–107.

ipocyo = the tail of the comet, its smoke
Here in This Year: Seventeenth-Century Nahuatl Annals of the Tlaxcala-Puebla Valley, ed. and transl. Camilla Townsend, with an essay by James Lockhart (Stanford: Stanford University Press, 2010), 65.