The term 'Cattle Rush' is a reference to the phenomenon of a STAMPEDE, which is an event in which a large herd of animals, usually cattle, run in a wild and uncontrolled manner. This term is often used to describe the mass migration of people during the 19th century American West, when settlers moved into the area in search of land and opportunity. The term 'STAMPEDE' is an 8-letter word that is used to describe this phenomenon.