The traditional name for the set of disasters that God inflicted on Egypt before the pharaoh let Moses lead the Israelites out of Egypt to the Promised Land. The plagues, as recorded in the Book of Exodus, included swarms of locusts, hordes of frogs, and a scourge of boils. After the tenth and most horrible plague, in which the angel of Death killed every Egyptian firstborn male child, including the pharaoh's son, the pharaoh finally freed the Israelites. (See Passover.)