Related Clues:

• Ringlike coral reef
• Christmas Island, for one
• Island surrounding a lagoon
• Lagoon border
• Caribbean island
• Reef in a ring
• Castaway's site, perhaps
• Key ring
• Lagoon formation
• 6-Down is part of it
• Land in the ocean
• Lagoon former
• Reef around a lagoon
• Island with a reef
• Coral island