tzompantli.

Headword: 
tzompantli.
Principal English Translation: 

skull rack (see attestations); also, a name for a tree in Mexico (tzompancuahuitl) is a synonym for tzompantli
Gran Diccionario Náhuatl, citing A. Wimmer 2004. https://gdn.iib.unam.mx/diccionario/tzompancuahuitl/75440 Translated here to English by Stephanie Wood.

Orthographic Variants: 
tzonpantli, tzunpantli
Attestations from sources in English: 

auh yn jtzontencō, tzompatitech conquauhço, iuh tlantica, yn iuh ipã omjc ynechichioal: ic vmpa ontlamj yn jnemjliz, vmpa reconquista yn jnemjliz, yn vmpa omjqujto Tlapitzaoaian = And his severed head they strung on the skull-rack. Thus he ended in the adornment in which he died. Thus he there ended his life, there he terminated his life, when he went to die there at Tlapitzauaian. (sixteenth century, Mexico City)
Fr. Bernardino de Sahagún, Florentine Codex: General History of the Things of New Spain; Book 2—The Ceremonies, No. 14, Part III, eds. and transl. Arthur J. O. Anderson and Charles E. Dibble (Santa Fe and Salt Lake City: School of American Research and the University of Utah, 1951), 68.

tzunpantlj = skull rack (central Mexico, sixteenth century)
Fray Bernardino de Sahagún, Primeros Memoriales, ed. Thelma D. Sullivan, et al. (Norman: University of Oklahoma Press, 1997), 119.

oncan quimanque yn intzonpan oncan oquihtoque ynic axcan ytocayocan tzompanco = There they laid out their skull rack where they called it Tzompanco, as its name now is. (central Mexico, early seventeenth century)
Codex Chimalpahin: Society and Politics in Mexico Tenochtitlan, Tlatelolco, Culhuacan, and Other Nahuatl Altepetl in Central Mexico; The Nahuatl and Spanish Annals and Accounts Collected and Recorded by don Domingo de San Antón Muñón Chimalpahin Quauhtlehuanitzin, eds. and transl. Arthur J. O. Anderson and Susan Schroeder (Norman: University of Oklahoma Press, 1997), vol. 1, 84–85.

auh in yehuatl yn huitzilopochtli niman ye quiteca yn itlach nimā ye quimana yn itzonpan = And then Huitzilopochtli built his ball court; then he laid out his skull rack (central Mexico, early seventeenth century)
Codex Chimalpahin: Society and Politics in Mexico Tenochtitlan, Tlatelolco, Culhuacan, and Other Nahuatl Altepetl in Central Mexico; The Nahuatl and Spanish Annals and Accounts Collected and Recorded by don Domingo de San Antón Muñón Chimalpahin Quauhtlehuanitzin, eds. and transl. Arthur J. O. Anderson and Susan Schroeder (Norman: University of Oklahoma Press, 1997), vol. 1, 80–81.