- (Mexico City): Cidade do México
- Méjico (rare, obsolete)
From Classical Nahuatl Mēxihco, originally a toponym for the Valley of Mexico. Aside from the element -co, the Nahuatl locative suffix, the etymology remains uncertain. It has been suggested to be derived from the name of Mēxihtli, a secret name for the patron god of the Aztec's, Huitzilopochtli, in which case the name could be interpreted as (“place where Huitzilopochtli lives”). Another hypothesis suggests the name to be a portmanteau of the words mētztli (“moon”) + xīctli (“navel”), giving the name the meaning (“place at the center of the moon”), referring to the city of Tenochtitlan's position in the middle of Lake Texcoco, which was part of a system of interconnected lakes whose shape was likened to that of a rabbit by the Aztecs; an animal associated to the moon. A third hypothesis suggests a derivation from Mēctli, the goddess of the maguey.
- (Mexico City): Ciudad de México