from Spanish, from Nahuatl (Aztecan) mexihco, the name of the ancient Aztec capital.
The etymology of this is opaque. Because of the difference in vowel length, it cannot be derived from ME-TL 'maguey.' The sequence XIH also differs in vowel length from XIC-TLI 'navel,' which has been proposed as a component element. The final element is locative -C(O). [Kartunnen]