Movies or TV series based on other fiction or history where the race of a character are non-Caucasian but are cast with Caucasian actors. Coined to describe the movie The Last Airbender where clearly asian characters of the anime series Avatar The Last Airbender are cast with white actors.
Avatar The Last Racebender was a terrible movie which had the main character Aang played by a white kid.
The Karate Kid remake does not count as a racebender, since the whole story was altered.
Al Jolson in The Jazz Singer wearing blackface was the first racebender.