Meaning & use
reef
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Meanings
nouncountable
A long, narrow ridge of rock, coral, or sand that lies at or just below the surface of the sea.
Grammar: Countable: a reef, two reefs, the Great Barrier Reef.
Patterns
- a coral reef
- a barrier reef
- on the reef
The boat struck a hidden reef and began to take on water.
Divers come from all over the world to explore the coral reef.
From the cliff top we could see the white foam where waves broke over the reef.
verbtransitivetechnical
To make a sail smaller by rolling or folding part of it, especially when the wind is strong.
Grammar: Takes an object: reef the sails. Often used in the passive: the sails were reefed.
Patterns
- reef the sails
- reef a sail
As the storm approached, the crew reefed the mainsail.
The captain ordered them to reef the sails before nightfall.
Word forms
| plural | reefs |
|---|---|
| third person singular | reefs |
| past tense | reefed |
| past participle | reefed |
| -ing form | reefing |
Common combinations
- coral reef
- The coral reef is home to thousands of species of fish.
- barrier reef
- The Great Barrier Reef stretches for over 2,000 kilometers.
- reef fish
- Colorful reef fish darted among the rocks.
- reef the sails
- The sailors reefed the sails as the wind grew stronger.
Synonyms and how they differ
- shoal
- A shoal is a sandbank or shallow area that can also be a reef, but it is usually made of sand and may be exposed at low tide.
- bank
- A bank is a raised area of the sea floor, often sand or mud, not necessarily rocky or coral.
- atoll
- An atoll is a ring-shaped coral reef or island, so it is a specific type of reef.
Word family
- reefy adjective
- Full of reefs; describing water that has many hidden rocks or coral.
Commonly confused: reef or riff?
reef vs riff
A riff is a repeated musical phrase, not a rock formation. The spelling and sound are similar, so check the context.
Practice
Choose the correct word: The ship was wrecked on a hidden ___ near the island.
Choose one answer.
A reef is a ridge of rock or coral in the sea, which can cause a shipwreck. A riff is a musical phrase; a reeve is a bird or an old official; a reefer is a refrigerated ship or a marijuana cigarette.
Make it your own
Write a sentence using “reef”, then check it and compare it with the examples above.