According to Wikipedia:

The terms multiracial, biracial, and mixed-race describe people whose ancestors are not of a single race. (Biracial strictly refers to those with ancestors from exactly two races). One example might be a mulatto, a person with a white and a black parent. Another might be the Mestizo who are descended from caucasian and indigenous ancestors. It is sometimes a matter of opinion if people are mixed-race, because races themselves are not clearly defined. This has caused some problems for census-takers.

Multiracial also describes a society or group that is composed of people from more than one racial or ethnic group. See also multicultural and coloured.

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