necoc.

Headword: 
necoc.
Principal English Translation: 

on both sides, square; from both sides; at both ends, two ways, both ways; from one side to the other (see Molina and attestations)

IPAspelling: 
nekok
Alonso de Molina: 

necoc. de ambas partes, o a vna parte y a otra, o avn lado y a otro. aduerbio.
Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1571, part 2, Nahuatl to Spanish, f. 65r. col. 1. Thanks to Joe Campbell for providing the transcription.

Frances Karttunen: 

NECOC on both sides, from or to one side and the other / de ambas partes, o a una parte y a otra, o a un lado y a otro (M). NEHNECOC redup. NECOC.
Frances Karttunen, An Analytical Dictionary of Nahuatl (Norman: University of Oklahoma Press, 1992), 161.

Horacio Carochi / English: 

necoc = on both sides, square; from both sides
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), 340-41, 507.

Andrés de Olmos: 

Necoc. de entramas partes, o de una y de otra.
Andrés de Olmos, Arte para aprender la lengua Mexicana, ed. Rémi Siméon, facsimile edition ed. Miguel León-Portilla (Guadalajara: Edmundo Aviña Levy, 1972), 184.

Attestations from sources in English: 

nauhtel yn huehuey calli yn nenecoc mamacuilmatl yhuan ca quezquitetl yn huehuey xacalli yvan yn acalcuezcomatl yvan yz cequi çan pilolcuezcomatl = four very large houses each [measuring] five matl across, large straw-roofed houses, and subterranean [?] granaries and some only subsidiary [?] granaries (central Mexico, early seventeenth century)
Codex Chimalpahin: Society and Politics in Mexico Tenochtitlan, Tlatelolco, Culhuacan, and Other Nahuatl Altepetl in Central Mexico; The Nahuatl and Spanish Annals and Accounts Collected and Recorded by don Domingo de San Antón Muñón Chimalpahin Quauhtlehuanitzin, eds. and transl. Arthur J. O. Anderson and Susan Schroeder (Norman: University of Oklahoma Press, 1997), vol. 2, 210–211.

necoc micoatiuh = there was death on both sides (Mexico City, sixteenth century)
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), 156.

nimā ie ic contlaça in acalchimalleque in tlatzontectli in impā in Españoles: necoccampa necoc in valhuetzi in tlatzontectli = Then the war-boat people hurled barbed darts at the Spaniards; from both sides the darts fell on them (Mexico City, sixteenth century)
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), 154.

çan necoc = on both sides
çan necoc cenpohualquahuitl = it is twenty quahuitl on both sides, or, twenty quahuitl square
Rebecca Horn, Postconquest Coyoacan: Nahua-Spanish Relations in Central Mexico, 1519–1650 (Stanford: Stanford University Press, 1997), 154.

yhuan in teopixque necoc motecpãtzinoque ynic hualmohuicaque = and the friars came in rows on both sides (early seventeenth century, central New Spain)
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), 44–45.

Attestations from sources in Spanish: 

cempohualli çan necoc yahualtic = veinte (brazas) a la redonda (Xochimilco, 1591)
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), 290–291.

necoc cenpouallalquauitl = veinte palos de ancho y largo
Vidas y bienes olvidados: Testamentos indígenas novohispanos, vol. 1, Testamentos en castellano del siglo XVI y en náhuatl y castellano de Ocotelulco de los siglos XVI y XVII, eds. Teresa Rojas Rabiela, Elsa Leticia Rea López, y Constantino Medina Lima (Santa Bárbara, Tamasolco, Tlaxcala, 1598), 306-307.

necoc = de ambos lados
Estudios de Cultura Náhuatl 15 (1982), 38.