reef
n. countable B1 Intermediate US //ˈɹif// UK //ɹˈiːf// reef
n. a long line of rocks, sand, or coral that sits just below or above the surface of the ocean. It can be a beautiful place for fish to live, but it is dangerous for ships.
n. a ridge of jagged rock, coral, or sand at or near the surface of the water. Often poses a significant navigational hazard to maritime vessels.
The boat hit a hidden reef and started taking on water.
Divers travel from all over the world to explore the vibrant life found within the tropical coral reef.
The captain navigated the shallow channel with extreme caution, knowing that the shifting sands of the reef could easily ground a ship of this size.
Usage
Commonly modified by 'coral', 'artificial', or 'barrier'.