Principal English Translation:
secret(s) (see Lockhart); or, a food storage place that held twenty years' worth of dried maize for the capital city, along with dried beans, chia, amaranth seeds, salt, chilies, squash seeds, etc. (see Sahagún)
Attestations from sources in English:
Petlacalco, vncan mopiaia, in jxqujch qualonj = Petlacalco: there was stored all the food (central Mexico, sixteenth century)
Fr. Bernardino de Sahagún, Florentine Codex: General History of the Things of New Spain; Book 8 -- Kings and Lords, no. 14, Part IX, 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), 44.
ca onontlachix in topco, petlacalco = What I have seen is a secret.
(central Mexico, 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), 60.