matlactli.

Headword: 
matlactli.
Principal English Translation: 

ten; theoretically, a reference to the ten fingers on the two hands (with maitl, hand, plus tlactli, bust or chest, which unites the two arms/hands) (see Siméon and Launey)

Orthographic Variants: 
matlactetl, mátlāctli, matlactle
IPAspelling: 
mɑhtɬɑktɬi
Alonso de Molina: 

matlactli. diez.
Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1571, part 2, Nahuatl to Spanish, f. 53r. col. 2. Thanks to Joe Campbell for providing the transcription.

Frances Karttunen: 

MAHTLAC-TLI ten / diez (M) This is abundantly attested across sources, and with the exception of X (which has MĀ) and R (which fails to indicate either vowel length or glottal stop), all agree on MAH for the first syllable. But in reduplicated form it is attested twice, both times as mātlātlaquilhuitica (Cf. 19V, 107r ). This reduplication is unusual in that it is the second syllable that reduplicates, as well as in the occurrence of MĀ for expected MAH.
Frances Karttunen, An Analytical Dictionary of Nahuatl (Norman: University of Oklahoma Press, 1992), 131–132.

Horacio Carochi / English: 

màtlactli =ten
Horacio Carochi, S.J., Grammar of the Mexican language with an explanation of its adverbs (1645), translated and edited with commentary by James Lockhart, UCLA Latin American Studies Volume 89 (Stanford: Stanford University Press, UCLA Latin American Center Publications, 2001), 506.

Lockhart’s Nahuatl as Written: 

distributive mahtlahtlactli.
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), 224.

Attestations from sources in English: 

ya matlacxivitl ya omme = now twelve years old (Cuernavaca region, ca. 1540s)
The Book of Tributes: Early Sixteenth-Century Nahuatl Censuses from Morelos, ed. and transl. S. L. Cline, (Los Angeles: UCLA Latin American Center Publications, 1993), 152–153.

yz ca yn imil çepovalli omatlactl- ynic patlavac caxtolmatl = Here is his field: 30 by 15 matl wide (Cuernavaca region, ca. 1540s)
The Book of Tributes: Early Sixteenth-Century Nahuatl Censuses from Morelos, ed. and transl. S. L. Cline, (Los Angeles: UCLA Latin American Center Publications, 1993), 150–151.

nochina yn ōpa temi tecuitlaapa matlactetl çecenpohualhuiyac = there are 10 chinampas of mine in Tecuitlaapan, each one 20 [units of measurement] long (Culhuacan, 1580)
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), 192.

inic matlactetl omume amoxtli = twelfth book
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), 50.

yz ca yn imil matlacmatli = Here is his field; it is ten units [in length]
(Cuernavaca, 1535–45)
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), 190.

Inic matlactetl omume amoxtli = Twelfth book
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), 50.

X tlamatlactlatepitzitzin = 10 little things (with holes drilled through them) (i.e. rosary beads?)
Robert Haskett and Stephanie Wood's notes from Nahuatl sessions with James Lockhart and subsequent research.

Seen abbreviated as "10ac" in a testament from Culhuacán, 1580. Later on we also see "11ac" for matlactli once.
Teresa Rojas Rabiela, Elsa Leticia Rea López, Constantino Medina Lima, eds., Vidas y bienes olvidados: Testamentos indígenas novohispanos, vol. 2, Testamentos en náhuatl y castellano del siglo XVI (Mexico: Consejo Nacional de Ciencias Tecnología, 1999) 226–227, 230–231.

ten; literally, chest (tlāctli) + hands
Michel Launey, An Introduction to Classical Nahuatl, translated and adapted by Christopher MacKay (Cambridge: Cambridge University Press, 2011), 169.

ichxquih matlactle ps ahu inin tomin tictzelia = a full ten pesos, and we receive this money (Azcapotzalco, 1738)
Beyond the Codices, eds. Arthur J.O. Anderson, Frances Berdan, and James Lockhart (Los Angeles: UCLA Latin American Center, 1976), Doc. 17, 102–103.

Attestations from sources in Spanish: 

Inic 10 tli 2 me = La doceava cosa (Coyoacán, 1624)
Vidas y bienes olvidados: Testamentos en náhuatl y castellano del siglo XVII, vol. 3, Teresa Rojas Rabiela, et al, eds. (México: CIESAS, 2002), 144–145.

matlactli = de maitl, mano, en comp. ma, y de tlactli, busto, torso del hombre, es decir, las dos manos [o, sea, diez dedos]
Rémi Siméon, Diccionario de la lengua náhuatl o mexicana (Mexico: Siglo XXI, 1988), xliv.

themes: 
Numbers, Math