multiethnic vs multiracial

multiethnic

adj
  • Of, pertaining to, or consisting of several ethnic groups. 

noun
  • A member of more than one ethnic group. 

multiracial

adj
  • Composed of, or having a mixture of, multiple races. 

noun
  • An individual of more than one race. 

How often have the words multiethnic and multiracial occurred in a corpus of books? (source: Google Ngram Viewer )