a place name, the altepetl of the Mexica, Mexico Tenochtitlan, or Mexico City as it was considered by the Spaniards -- sometimes considered to include Tlatelolco, also inhabited by Mexica
"In Chimalpahin 'Mexico' still has the traditional Nahuatl meaning of the area inhabited by the Mexica in the narrower ethnic sense, limited to Tenochtitlan and Tlatelolco; sometimes the meaning seems to be Tenochtitlan only, and sometimes the whole mixed Spanish-indigenous capital of New Spain. Yet since the indigenous connotation still predominates, we have not felt it appropriate to translate 'Mexico City' except in the relatively few instances where the Spanish loanword ciudad is used in addition. Let the reader understand, then, that 'Mexico' in our translation refers approximately to the area now called Mexico City. The term was not yet and long afterward would not be used for New Spain as a whole or for the country we call Mexico today."
ca nel mexico in ticate ca ic mani ĩ mexicayotl = For verily in Mexico were we, and thus persisted the reign of Mexico (central Mexico, sixteenth century)
ynic tiquimittazque yn ixquich yn techyahuallotoc yxquich tiquinpehuazque tiquimaçizque. yc maniz yn taltepeuh mexico. tenochtitlan. quauhtli ypipitzcayan ynetomayan. quauhtli ytlaquayan. yhuan michin ypatlanian. yhuan cohuatl yçomocayan = Thus shall we find all who lie surrounding us, all whom we shall conquer, whom we shall capture. Thus will our altepetl of Mexico Tenochtitlan be, the place where the eagle screeches and stretches itself; where the eagle eats and the fish fly and the serpent hisses.... (central Mexico, early seventeenth century)