The Aztec /ˈæztɛk/ people were certain ethnic groups of central Mexico, particularly those groups who spoke the Nahuatl language and who dominated large parts of Mesoamerica from the 14th to 16th centuries. The Nahuatl words aztecatl [asˈtekat͡ɬ] (singular) and aztecah [asˈtekaʔ] (plural) mean "people from Aztlán", a mythological place for the Nahuatl-speaking culture of the time, and later adopted as the word to define the Mexica people. Often the term "Aztec" refers exclusively to the Mexica people of Tenochtitlan (now the location of Mexico City), situated on an island in Lake Texcoco, who referred to themselves as Mēxihcah Tenochcah [meːˈʃiʔkaʔ teˈnot͡ʃkaʔ] or Cōlhuah Mexihcah [ˈkoːlwaʔ meːˈʃiʔkaʔ].
Sometimes the term also includes the inhabitants of Tenochtitlan's two principal allied city-states, the Acolhuas of Texcoco and the Tepanecs of Tlacopan, who together with the Mexica formed the Aztec Triple Alliance which controlled what is often known as the "Aztec Empire". In other contexts, Aztec may refer to all the various city states and their peoples, who shared large parts of their ethnic history and cultural traits with the Mexica, Acolhua and Tepanecs, and who often also used the Nahuatl language as a lingua franca. In this meaning it is possible to talk about an Aztec civilization including all the particular cultural patterns common for most of the peoples inhabiting Central Mexico in the late postclassic period.