1. a large circular or oval building with rows of seats rising in tiers around a central open space, used for entertainment or sports
2. a semicircular seating arrangement, especially in a lecture hall or theater
3. a natural formation resembling an amphitheater, such as a valley surrounded by hills
Usage: geological

Examples

• The Roman Colosseum is the most famous amphitheater in the world.
• Students filled every seat in the medical school’s amphitheater for the lecture.
• The outdoor amphitheater hosts concerts during the summer months.
• We sat in the upper tier of the amphitheater to get a better view.
• The valley formed a natural amphitheater surrounded by towering cliffs.
• The university built a new amphitheater for large chemistry classes.
• Ancient gladiators fought in amphitheaters throughout the Roman Empire.