blockbuster (n.)

also block-buster, 1942, "large bomb" (4,000 pounds or larger, according to some sources), from block (n.1) in the "built-up city square" sense, on the notion of the widespread destruction they could cause. Entertainment sense "spectacularly successful production" is attested by 1952. 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.