a large amphitheater in Rome whose construction was begun by Vespasian about AD 75 or 80
"Visitors to the Colosseum can trace its history back to Emperor Vespasian, who began constructing the massive Roman amphitheater around AD 75."
Alternative spelling of coliseum
"After visiting the famous Roman arena, our guide jokingly referred to it as the Colosseum before correcting himself to say we should use the less common alternative spelling, Coliseum."
The largest stadium in the Roman empire, located near the center of Rome.
"Visitors flocked to the Colosseum to marvel at the massive ruins of what was once the largest stadium in the Roman Empire."