cuaitl.

Headword: 
cuaitl.
Principal English Translation: 

the human head, or, the top or the end of something
James Lockhart, Nahuatl as Written: Lessons in Older Written Nahuatl, with Copious Examples and Texts (Stanford: Stanford University Press and UCLA Latin American Studies, 2001), 230.

also: summit, peak, apex (see Karttunen)

Orthographic Variants: 
quaitl
Alonso de Molina: 

quaitl. estremidad de algo, o la cabeza. s. lo alto della como es la superficie del caxco, vertex.
Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1571, part 2, Nahuatl to Spanish, f. 84r. col. 2. Thanks to Joe Campbell for providing the transcription.

Frances Karttunen: 

CUĀ(I):-TL head; top, summit, peak / extremidad de algo, o la cabeza ... lo alto de ella como es la superficie del casco, vértice (M) In the derived form CUAHNĀMIQU(I), this has the alternate stem form CUAH-, making it analogous to MĀ(I)-TL ~MAH .
Frances Karttunen, An Analytical Dictionary of Nahuatl (Norman: University of Oklahoma Press, 1992), 58.

Lockhart’s Nahuatl as Written: 

combining form most often quā-, sometimes quah. 230

Attestations from sources in English: 

tocuā = (our) head
Michel Launey, An Introduction to Classical Nahuatl, translated and adapted by Christopher MacKay (Cambridge: Cambridge University Press, 2011), 97.

quaitl (noun) = head, top, summit
Daniel Garrison Brinton, Ancient Nahuatl Poetry: Containing the Nahuatl Text of XXVII Ancient Mexican Poems (1877), 160.

Tocuezco = Crown of the head; quanepantlatli = the middle of the head; toquanepantla = the middle of our head; quateuilachiuhcaiutl = the roundness of the head (central Mexico, sixteenth century)
Fr. Bernardino de Sahagún, Florentine Codex: General History of the Things of New Spain; Book 10 -- The People, No. 14, Part 11, 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, 1961), 100.

nicquitequi = I hit him on the head; nicquatlapana = I break his head; nicquatzaiana = I split his head; nicquatelicça = I kick his head; nicquatlatzinia = I make his head ring; nicquatetexoa = I brain him; nicquatepinia = I hit his head with my fist; nicquatepitzinia = I bash his head; nicquapitzinia = I smash his head; nicquacoionia = I pierce his head; xipetziui = it becomes smooth (central Mexico, sixteenth century)
Fr. Bernardino de Sahagún, Florentine Codex: General History of the Things of New Spain; Book 10 -- The People, No. 14, Part 11, 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, 1961), 99.

Attestations from sources in Spanish: 

Yn ocentetl ça no ocan mani yquapan = Y ahí mismo está otra, a la cabezada (Santa Bárbara Tamasolco, Tlaxcala, 1596)
Vidas y bienes olvidados: Testamentos indígenas novohispanos, vol. 1, Testamentos en castellano del siglo XVI y en náhuatl y castellano de Ocotelulco de los siglos XVI y XVII, eds. Teresa Rojas Rabiela, Elsa Leticia Rea López, y Constantino Medina Lima (Mexico: CIESAS, 1999), 330–331).

la cabeza
Gran Diccionario Náhuatl, citing Rincón 1595, Carochi 1645, Clavijero 1780, and more. See, for example, https://gdn.iib.unam.mx/diccionario/cuaitl/19730.

See also: