tepiltzin.

Headword: 
tepiltzin.
Principal English Translation: 

somebody's child, whether a son or a daughter (see Molina); offspring, someone well born (see Karttunen); a noble (see Sahagún)

IPAspelling: 
teːpiltsin
Alonso de Molina: 

tepiltzin. hijo, o hija de alguno.
Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1571, part 2, Nahuatl to Spanish, f. 103r. col. 1. Thanks to Joe Campbell for providing the transcription.

Frances Karttunen: 

TĒPILTZIN offspring, someone wellborn / hijo o hija de alguno (M), bien nacido (C) [(2)Cf.99r,128r]. This is -PIL 'offspring' prefixed with the prefix TĒ-, which imparts a generic sense 'offspring of someone,' and the honorific element -TZIN. C contrasts this with TEPILTZIN, the honorific form of TEPIL-LI 'vulva.' See -PIL.
Frances Karttunen, An Analytical Dictionary of Nahuatl (Norman: University of Oklahoma Press, 1992), 230.

Attestations from sources in English: 

in tepiltzin, nane, tate taoa, tequixti, cemoquichtli centeconetl, teach, teiccauh, iacapantli, tlacoeoa, xocoiutl ueltioa, iccaue, cule, cioa, tlaçotli, tlaçotlaloni, neneconi, tlatlaçotlaloni, teiolloimecaio, aixcaoaloni, axiccaoaloni, tlaxexeluiloni. = The noble has a mother , a father. He resembles his parents. [He is] an only man, an only child, an older brother, a younger brother, a first born, a second child, [or] a youngest sister; he has a grandfather, a grandmother. [He is] esteemed, lovable, good of lineage; not to be neglected, not to be ignored. [He is] one to share things with. (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), 19.

tepil = the son, the child
tepilhuan (plural) = the children, the next generation, those who will inherit the town; the nobles; the population
James Lockhart, personal communication, May 23, 2008.

Attestations from sources in Spanish: 

canel yte[c]h quitazque yn tepilhuan yn canin mani yn altepetlalli = en él los hijos verán de verdad dónde están situadas las tierras del pueblo
Anneliese Monnich, "El Altepeamatl de Ocoyacac, México," Indiana 2 (1974), 171.