1. A precious jewel that is part of or featured on a monarch's or sovereign's regalia. Just one crown jewel from the Queen's regalia is worth enough money to buy a small country.

2. An asset or possession prized as being the best of a group of similar things. This vintage 1965 Corvette Stingray is the crown jewel of my car collection. The works of Shakespeare are the crown jewels of English drama.