sanctum /sangkˈtəm/

1. (esp in the phrase inner sanctum) a sacred place
2. A (very) private room

sanctum sanctorum noun

1. The holy of holies, the inner chamber of the Jewish tabernacle
2. Any specially reserved retreat or room (informal)

• ring in
• ringing
• ringingly
• ringings
• ringing tone
• ringing tones
• ringleader
• ringleaders
• ringless
• ringlet
• ringleted
• ringlets
• ring main
• ring mains
• ringman
• ring mark
• ring marks
• ringmaster
• ringmasters
• ringmen
• ring money
• ring-necked
• ring network
• ring networks
• ring off