Principal English Translation:
on both sides, square; from both sides; at both ends; Molina says it is the same as necoc
Alonso de Molina:
necoccampa. lo mesmo es que necoc.
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:
NECOCCĀMPA from or toward both sides / de ambas, o desde ambas, o hacia ambas partes (M) [(3)Cf.92r]. See NECOC, -CĀN, -PA.
Frances Karttunen, An Analytical Dictionary of Nahuatl (Norman: University of Oklahoma Press, 1992), 161.
Attestations from sources in English:
necoccampa in valminaloia in tlatzontectica, yoan necoccampa in valtepacholo = From both sides there was shooting [at the Spaniards] with barbed darts, and stones were thrown from both sides.
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), 194.
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.
Attestations from sources in Spanish:
necoccanpa nenemi coaxo[c]htli netztimani = por ambos lados pasa el límite, se extiende [This is from a Techialoyan manuscript.]
Anneliese Monnich, "El Altepeamatl de Ocoyacac, México," Indiana 2 (1974), 172.