White chocolate
For official and legal purposes, such as for imports or exports, it is illegal not only in the U.S. but in the entire civilized world to equate white chocolate with "real" chocolate because white chocolate does not contain cocoa.

Nearly every country in the world subscribes to the Harmonized Tariff System, a listing of every commodity, product and material thing in the world. The HTS breaks down nearly everything there is into 98 chapters. Chapter 18 covers "Cocoa and Cocoa Preparations" and includes chocolate and chocolate products (in great detail). Chapter 17 covers "Sugars and Sugar Confectionery" including, under heading 1704: "Sugar confectionery (including white chocolate), not containing cocoa". Notes and interpretations of this monumental work make it clear that the term "white chocolate" does not mean that the product is actually chocolate, which, in fact, it is not because it does not contain cocoa; the term is used in 1704 only because it's a common name for what is actually a sugar confection.

Hence, we learn that "white chocolate" is a kind of oxymoron.