the.com/pit bull

means A short-haired, muscular dog breed (or group of related breeds) originally developed for strength and gameness, now also used loosely as a label — often unfairly — for aggressive or dangerous dogs.

from From 'pit' + 'bull,' tracing back to 19th-century England, where bulldogs were bred for bull-baiting — pitting dogs against tethered bulls in blood sport arenas called pits. When that was banned, breeders turned to 'pit sports' instead: dogfighting, staged in the same pits, which favored dogs crossing bulldog tenacity with terrier speed. That cross became the 'pit bull terrier.' The name has carried the stigma of the pit ever since, even as most pit bulls today have never seen one.