The Colosseum was the sports stadium in ancient Rome.
The definition of a coliseum is any large sports stadium. The Colosseum was the name of the oval coliseum or amphitheater in the center of the city of ancient Rome. The Colosseum is also known as the Flavian Amphitheatre. It was built in about 1 AD by Emperor Vespasian. It is still the largest amphitheater, or theatre in the round, in the world.