elpantli.

Headword: 
elpantli.
Principal English Translation: 

the chest or the breasts (see Molina)

IPAspelling: 
eːlpɑntɬi
Alonso de Molina: 

elpantli. el pecho o los pechos.
Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1571, part 2, Nahuatl to Spanish, f. 28v. col. 2. Thanks to Joe Campbell for providing the transcription.

Frances Karttunen: 

ĒLPAN-TLI breast, bosom / el pecho o los pechos (M) [(2)Zp.95,158]. See ĒL-LI, -PAN.
Frances Karttunen, An Analytical Dictionary of Nahuatl (Norman: University of Oklahoma Press, 1992), 78.

Attestations from sources in English: 

elpantli = chest;
telpan = our chest;
tlapatlaoa = that which broadens;
tlatilaoa = that which thickens;
nacaio, nacaio [nacayo] = fleshy;
nacatilaoac = of thick flesh;
nacacanaoac = of thin flesh;
nacatotochtic = of sparse flesh;
patlaoa = it broadens;
tilaoa = it thickens;
uecapaniui [huecapanihui] = it expands;
nanatziui = it fattens;
comoliui [comolihui] = it becomes hollowed;
acaliui [acalihui] = it becomes grooved (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), 118.