Courtesy: WikipediaMexico City, which was founded in 1524 on top of the ancient Aztec capital of México-Tenochtitlan. The name comes from the Nahuatl language, but its meaning is not known. It has been suggested that it is derived from Mextli or Mēxihtli, a secret name for the god of war and patron of the Aztecs, Huitzilopochtli, in which case Mēxihco means "Place where Mēxihtli lives".
Another hypothesis suggests that the word Mēxihco derives from the mētztli ("moon"), xictli ("navel", "center" or "son"), and the suffix -co (place), in which case it means "Place at the center of the moon" or "Place at the center of the Lake Moon", in reference to Lake Texcoco. The system of interconnected lakes, of which Texcoco was at the center, had the form of a rabbit, the same image that the Aztecs saw in the moon. Tenochtitlan was located at the center (or navel) of the lake (or rabbit/moon). Still another hypothesis suggests that it is derived from Mēctli, the goddess of maguey.
The name of the city was transliterated to Spanish as México with the phonetic value of the x in Medieval Spanish, which represented the voiceless postalveolar fricative /ʃ/. This sound, as well as the voiced postalveolar fricative /ʒ/, represented by a j, evolved into a voiceless velar fricative /x/ during the sixteenth century. This led to the use of the variant Méjico in many publications in Spanish, most notably in Spain, whereas in Mexico and most other Spanish–speaking countries México was the preferred spelling. In recent years the Real Academia Española, which regulates the Spanish language, determined that both variants are acceptable in Spanish but that the normative recommended spelling is México. The majority of publications in all Spanish-speaking countries now adhere to the new norm, even though the alternative variant is still occasionally used. In English, the x in Mexico represents neither the original nor the current sound, but the consonant cluster /ks/.
The official name of the country has changed as the form of government has changed. On two occasions (1821–1823 and 1863–1867), the country was known as Imperio Mexicano (Mexican Empire). All three federal constitutions (1824, 1857 and 1917, the current constitution) used the name Estados Unidos Mexicanos—or the variants Estados Unidos mexicanos and Estados-Unidos Mexicanos, all of which have been translated as "United Mexican States". The term República Mexicana, "Mexican Republic" was used in the 1836 Constitutional Laws.