Definition of Mexico City in US English:
Mexico City
proper noun
The capital of Mexico; population 8,720,916 (2005). Founded in about 1300 as the Aztec capital Tenochtitlán, it was destroyed in 1521 by the Spanish conquistador Cortés, who rebuilt it as the capital of New Spain.
Pronunciation
Mexico City
/ˌmeksəkō ˈsidē/