petlatl.

Headword: 
petlatl.
Principal English Translation: 

reed mat (loaned to Spanish as petate)
S. L. Cline, Colonial Culhuacan, 1580-1600: A Social History of an Aztec Town (Albuquerque: University of New Mexico Press, 1986), 236.

IPAspelling: 
petɬɑtɬ
Alonso de Molina: 

petlatl. estera generalmente.
Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1571, part 2, Nahuatl to Spanish, f. 81r. col. 1. Thanks to Joe Campbell for providing the transcription.

Frances Karttunen: 

PETL(A)-TL pl: -MEH woven mat, petate / estera generalmente (M), petate (T).
Frances Karttunen, An Analytical Dictionary of Nahuatl (Norman: University of Oklahoma Press, 1992), 192.

Lockhart’s Nahuatl as Written: 

combining form petla-.

Attestations from sources in English: 

yhuan Mexica cequintin yn timacehualtin tlapallehuique quinnapalloque in mimicque yn atle andas quipia çan petlatica ynic quinhuicaque quintocato = some of us Mexica commoners helped; they carried the dead, who had no biers; they just took them in mats to bury them. (central Mexico, 1612)
Annals of His Time: Don Domingo de San Antón Muñón Chimalpahin Quauhtlehuanitzin, James Lockhart, Susan Schroeder, and Doris Namala, eds. and transl. (Stanford: Stanford University Press, 2006), 224–225.

in aztapilpetlatl, in astapilpepechtli = the [white and green] reed mats, the reed beds
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), 75.

in ipetl, in icpal = his seat of authority
James Lockhart, We People Here: Nahuatl Accounts of the Conquest of Mexico, Repertorium Columbianum v. 1 (Los Angeles: UCLA Center for Medieval and Renaissance Studies, 1993), 62.

in totechiuhcaoan yn ochpanaco, in tlatzonjlpico in tlatepachoco: injc contetecatiaque in petlatl, in icpalli = those who came clearing the way, who came clearing the trees, who came clearing the stones, so that they established the realm
Fr. Bernardino de Sahagún, Florentine Codex: General History of the Things of New Spain; Book 6 -- Rhetoric and Moral Philosophy, No. 14, Part 7, 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), 68.

petlatolli petlatl mochiva ypetlayo in vevey calli = mat rushes, from which mats are made—the great houses’ particular mats (central Mexico, sixteenth century)
Fray Bernardino de Sahagún, Primeros Memoriales, ed. Thelma D. Sullivan, et al. (Norman: University of Oklahoma Press, 1997), 226.

Quimunilvia. nopiltzitzine, cuix quiçaz yn ihiyotzin yn petlatl, yn icpally ca omoçentecac = They said to them: “My sons, by chance will the words of the mat, of the seat come forth?” (central Mexico, sixteenth century) (central Mexico, sixteenth century)
Fray Bernardino de Sahagún, Primeros Memoriales, ed. Thelma D. Sullivan, et al. (Norman: University of Oklahoma Press, 1997), 231.

Mach iuqui aauayo ipan ticmati tlatoani, anozo petlatl icpalli: iuhquin auitzyo ipan ticmati, ixpan timoteiluitinemi. Azo muchipa moteiluia: cenca quitequipachotinemi in tlatoani = "Do you think that the king or the throne has no thorns? When you bring your dispute before him or when accusations are forever being made against others, do you think he has no briers? He is extremely vexed!" (central Mexico, sixteenth century)
Thelma D. Sullivan, "Nahuatl Proverbs, Conundrums, and Metaphors, Collected by Sahagún," Estudios de Cultura Náhuatl 4 (1963), 146–147.

nopetl = my mat (petlatl)
(This has a first person possessor plus a shortened form of petlatl, meaning my mat. At first glance this might appear to be a noun with its absolutive ending, but the short vowel that might have appeared at the end has dropped away.)
Michel Launey, An Introduction to Classical Nahuatl, translated and adapted by Christopher MacKay (Cambridge: Cambridge University Press, 2011), 91.

petlatl icpalli = "the mat, the high-backed seat," i.e. rulership; in the time of the ancestors (prehispanic times) commoners did not dare sit on this seat
David Tavárez, The Invisible War: Indigenous Devotions, Discipline, and Dissent in Colonial Mexico (Stanford: Stanford University Press, 2011), 44.

in mopetlapantzinco, in mocpalpantzinco = thy reed mat, thy reed seat (central Mexico, sixteenth century)
Fr. Bernardino de Sahagún, Florentine Codex: General History of the Things of New Spain; Book 6 -- Rhetoric and Moral Philosophy, No. 14, Part 7, 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), 17.

cujx nolujl, cujx nomaceoal in cujtlatitlan, in tlaҫultitlan in tinechmanjlia? in petlapan, in jcpalpan tinechmotlalilia = It is perhaps my desert, my merit that thou takest me from the excrement, from the filth, that thou placest me on the reed mat, on the reed seat (central Mexico, sixteenth century)
Fr. Bernardino de Sahagún, Florentine Codex: General History of the Things of New Spain; Book 6 -- Rhetoric and Moral Philosophy, No. 14, Part 7, 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), 41.

Auh in oacic navilhvitl: njman inpetl meoa = And when four days had passed, then their straw mat was raised (central Mexico, sixteenth century)
Fr. Bernardino de Sahagún, Florentine Codex: General History of the Things of New Spain; Book 6 -- Rhetoric and Moral Philosophy, No. 14, Part 7, 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.

in vncan qujҫa in totecuioan in tetecutin, in tlatoque, in apia, in tepepia, in vncan qujҫa in petlati, in jcpalti, in vncan qujnmanjlia, in vncan qujnmopepenjlia in totecujo, in tloque, naoaque, in quauhpetlatl, in ocelopetlatl ipan cate: in jnmac manj in quauhxicalli, in quauhpiaztli = Thence emerge our lords, the lords, the rulers, the guardians of the city; thence emerge those assume the reed mat, the reed seat of authority, whom our lord, the lord of the near, of the nigh, setteth there, selecteth there: those who are of the order of eagles, those of the order of ocelots; those in whose hands rest the eagle vessel, the eagle tube (central Mexico, sixteenth century)
Fr. Bernardino de Sahagún, Florentine Codex: General History of the Things of New Spain; Book 6 -- Rhetoric and Moral Philosophy, No. 14, Part 7, 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), 214.

Attestations from sources in Spanish: 

Yn petlatl ycpalli yn tecpayotl çan no iuhqui yn Diego yn imon = El petate, la silla y el hilado también son para Diego y su yerno Bartolomé (Tulancingo, México, 1577)
Vidas y bienes olvidados: Testamentos indígenas novohispanos, vol. 2, Testamentos en náhuatl y castellano del siglo XVI, eds., Teresa Rojas Rabiela, Elsa Leticia Rea López, Constantino Medina Lima (Mexico: Consejo Nacional de Ciencias Tecnología, 1999), 190–191.

petlatl = estera; mopetl = tu estera
Rémi Siméon, Diccionario de la lengua náhuatl o mexicana (Mexico: Siglo XXI, 1988), xlii.