Half-caste is a term used for individuals of multiracial descent. It is derived from the term caste, which comes from the Latin castus, meaning pure, and the derivative Portuguese and Spanish word casta, meaning race. Terms such as half-caste, caste, quarter-caste and mix-breed were used by colonial officials in the British Empire during their classification of indigenous populations, and in Australia used during the Australian government's pursuit of a policy of assimilation. In Latin America, the equivalent term for half-castes was Cholo and Zambo. Some people now consider the term offensive.

The terms multiracial people or mixed-race people refer to people who are of more than one race, and the terms multi-ethnic people or ethnically mixed people refer to people who are of more than one ethnicity. A variety of terms have been used both historically and presently for mixed-race people in a variety of contexts, including multiethnic, polyethnic, occasionally bi-ethnic, Métis, Muwallad, Melezi, Coloured, Dougla, half-caste, ʻafakasi, mestizo, mutt, Melungeon, quadroon, octoroon, sambo/zambo, Eurasian, hapa, hāfu, Garifuna, pardo, and Gurans. A number of these once-acceptable terms are now considered offensive, in addition to those that were initially coined for pejorative use.