Castizo (Spanish: [kasˈtiθo] or [kasˈtiso]) is a Spanish word with a general meaning of "pure", "genuine" or representative of its race (from the Spanish: "casta"). The feminine form is castiza. From this meaning it evolved other meanings, such as "typical of an area" and it was also used for one of the colonial Spanish race categories, the castas, that evolved in the 17th century. In Latin America Castizo is used to describe the individuals with an admixture of 75% European and 25% Native American.
Under the caste system of colonial Spanish America, the term originally applied to the offspring resulting from the union of a European and a mestizo; that is, someone of three quarters European and one quarter Amerindian ancestry. During this era, some other terms (mestizo, cuarterón de indio, etc.) were in use to denote other individuals of mixed European and Amerindian ancestry in ratios smaller or greater than that of castizos.
Under this same caste system, the offspring of a Spaniard and a Castiza was classified as a criollo (legally, a Spaniard born in the Americas), thus the offspring regained his or her purity of blood. (See the related concept of Limpieza de sangre.) For castizos whose residual quarter of Amerindian ancestry was not apparent at all, many simply consolidated themselves within the criollos and Peninsulares (Spaniards born in Spain).
With the fall of the Spanish Empire, the numerous caste terminologies fell out of use and lost all meaning, other than the categories of White, Black, Amerindian, and their three possible resulting combinations: mestizo, mulato and zambo (the latter three, now without blood quantum connotations), as these legal categories were seen as incompatible with the new concept of citizenship.