multiracial (adj.)

before vowels mult-, word-forming element meaning "many, many times, much," from combining form of Latin multus "much, many," from PIE *ml-to-, from root *mel- (2) "strong, great, numerous." It was much-used in forming Latin compounds in classical times and after (such as multianimis "having much courage," multibibus "much-drinking," multicomus "having much hair," multiloquus "talkative"). Many English words that use it (multinational, etc.) are 20c. coinages.

"relating, pertaining to, or characteristic of an ethnic race or race generally," 1862, from race (n.2) + -ial. "A word of considerable frequency in the 20th century" [OED]. Related: Racially.