Related Clues:

• Reef
• Island ring
• A-test site, perhaps
• Geometrical solid
• Bikini, e.g.
• Ring around a lagoon
• Doughnut's shape
• Reef, maybe
• Wake Island, e.g.
• Coral formation
• Castaway's site
• It has a certain ring to it
• Good snorkeling site
• Makin, for one
• Ring-shaped coral reef