What is the X in X-mas?
also block-buster, big bomb (4,000 pounds or larger, according to some sources), 1942, from block (n.) in the "built-up city square" sense. Entertainment sense is attested from 1957. U.S. sense of "real estate broker who sells a house to a black family on an all-white neighborhood," thus sparking an exodus, is from 1955.
A great success; a lavish and popular film, show, etc: A gangster movie can be a box-office blockbuster
[1950s+; fr the large high-explosive aerial bombs of World War II called blockbusters]
A real-estate dealer who blockbusts (1960s+)