reef

Everyday

1. A reef is a long ridge of rock, sand or coral just under or at the surface of the sea. tree →
2. A coral reef is built over many years by tiny sea animals called corals and is home to huge numbers of fish and other sea creatures. tree →
3. (sailing) To reef a sail means to roll or tie up part of it to make it smaller in strong wind. tree →

In the lessons

In science and geography lessons reefs come up in ocean habitats and climate: the Great Barrier Reef off Australia is the largest coral reef system in the world and can be seen from space; warmer, more acidic seas can cause «coral bleaching», when corals turn white and may die. In stories, ships wreck on hidden reefs. In safety lessons, swimmers learn that reefs can be sharp and waves break hard over them.

Examples

• The Great Barrier Reef is off the coast of Queensland, Australia. tree →
• Clownfish hide in the anemones on the reef. tree →
• The ship hit a reef and sank. tree →
• Coral reefs are full of colourful fish. tree →
• Warm water can make the reef turn white. tree →
• Divers must not touch or break the coral reef. tree →
• The sailors reefed the sails as the storm grew stronger. tree →

Note

Plural «reefs» (not «reeves»). Countable: «a reef». Coral is made by animals, not plants, though it looks like rock or plants. Do not confuse with «wreath» (a ring of flowers) or «reek» (a bad smell).