Chichimec (chēchēmek') [key], general term for the peoples of the Valley of Mexico between the periods of Toltec ascendancy and Aztec ascendancy. Before the 11th cent. the Chichimec were nomadic peoples on the northern fringes of the valley. The Chichimec period (c.950–1300) was one of intertribal warfare and political confusion, but it prepared the way for the tributary empire of the Aztec.
