tetzahuac.

Headword: 
tetzahuac.
Principal English Translation: 

something thick, sticky, congealed, hardened (see Molina and Karttunen)

Orthographic Variants: 
tetzauac, tetzaoac
IPAspelling: 
tetsɑːwɑk
Alonso de Molina: 

tetzauac. cosa espessa desta manera.
Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1571, part 2, Nahuatl to Spanish, f. 111r. col. 1. Thanks to Joe Campbell for providing the transcription.

Frances Karttunen: 

TETZĀHUAC something thick, sticky, congealed, hardened / cosa espesa (M), viscoso, pegajoso, espeso (T) [(1)Tp.226,(3)Zp.56,130,222]. See TETZĀHU(A).
Frances Karttunen, An Analytical Dictionary of Nahuatl (Norman: University of Oklahoma Press, 1992), 236.

Attestations from sources in English: 

tetzaoac = thick (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), 132.