made up of or involving or acting on behalf of various races; "a multiracial society"; "multiracial government"

relating to or made up of many races.

The terms multiracial, biracial, and mixed-race describe people who are not easily classified into a single race. (Biracial refers to those with ancestors from mostly two races). It is sometimes a matter of opinion if people are mixed-race, because races themselves are not clearly defined.