1. a large amphitheater or stadium, especially one used for sports or entertainment
2. the Colosseum, the famous ancient Roman amphitheater in Rome
Usage: proper noun when capitalized

Examples

• The ancient colosseum could hold thousands of spectators.
• Gladiators fought in the Roman Colosseum nearly two thousand years ago.
• The modern sports colosseum was packed with cheering fans.
• Tourists from around the world visit the Colosseum in Rome.
• The university built a new colosseum for basketball games.
• Wild animals were once kept beneath the Colosseum’s arena floor.
• The concert was held in the city’s largest colosseum.