# reef

/ˈɹif/ (US) · /ɹˈiːf/ (UK)

Source: https://englishreference.com/word/reef
Updated: 2026-08-15

## Senses

### 1. underwater ridge

noun · CEFR B1

a long line of rocks, sand, or coral just below or at the surface of the ocean.

For teachers: a ridge of jagged rock, coral, or sand just above or below the surface of the sea.

- The boat hit a hidden reef and started taking on water.
- The Great Barrier Reef consists of thousands of individual coral formations that support a vast array of marine biodiversity.

### 2. part of a sail

noun · CEFR C2 · Technical

a part of a sail that you can roll up or fold to make the sail smaller when the wind is too strong.

For teachers: a specific portion of a sail that is rolled or folded and secured to reduce the effective surface area in high winds.

- The captain decided to take a reef in the mainsail as the storm approached.
- With the gale force winds increasing, the crew struggled to tie down the second reef before the vessel began to heel dangerously.

### 3. to reduce sail area

verb · CEFR C2 · Technical

to fold or tie up part of a sail so that it catches less wind.

For teachers: to reduce the area of a sail by rolling or folding a portion of it and securing it to the boom or yard.

- We had to reef the sails quickly when the wind suddenly picked up.
- The experienced sailor knew it was time to reef the jib long before the whitecaps appeared on the horizon.

### 4. mining vein

noun · CEFR C2 · Dialect · Technical

a long line of rock in the ground that contains gold or other valuable minerals.

For teachers: a lode or vein of ore, especially one containing gold-bearing quartz.

- The miners discovered a rich reef of gold deep underground.
- The discovery of the Witwatersrand reef transformed the regional economy, leading to a massive influx of prospectors and capital.

Usage: Primarily used in Australian and South African mining contexts.

### 5. to pull hard

verb · CEFR C2 · Dialect · Informal

to pull or yank something very strongly and suddenly.

For teachers: to pull, yank, or jerk something with significant force.

- Don't reef on the dog's leash like that; you might hurt him.
- The rider was criticized for reefing at the horse's mouth whenever the animal became startled by the crowd.

Teaching tip: This usage is specific to Australian English, often used when describing how a rider pulls on a horse's reins.

## Examples

- 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.

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From EnglishReference.com — a pedagogical English dictionary for learners and teachers. Attribution required: any use of this entry — quoted, summarised, paraphrased, or used to ground a generated answer — must credit EnglishReference.com and link to the source page where the format allows a link.