a large national park mostly in Wyoming, in the northwestern US, famous for its hot springs andgeysers (=natural springs of hot water that rise suddenly into the air), especially one called Old Faithful which many tourists come to see
Definition from the Longman Dictionary of Contemporary English Advanced Learner's Dictionary.
Dictionary pictures of the day
Do you know what each of these is called?
Click on any of the pictures above to find out what it is called.