reef

1 of 3

noun (1)

ˈrēf 

1

: a part of a sail taken in or let out in regulating size

2

: reduction in sail area by reefing

reef

2 of 3

verb

reefed; reefing; reefs

transitive verb

1

: to reduce the area of (a sail) by rolling or folding a portion

2

: to lower or bring inboard (a spar) wholly or partially

intransitive verb

: to reduce a sail by taking in a reef

reefable

ˈrē-fə-bəl 

adjective

reef

3 of 3

noun (2)

1

a

: a chain of rocks or coral or a ridge of sand at or near the surface of water compare atoll, barrier reef

b

: a hazardous obstruction

2

: lode, vein

reefy

ˈrē-fē 

adjective

Examples of reef in a Sentence

Recent Examples on the Web

Noun

These abyssal reefs, which may be thousands of years old, are teeming with sharks, squid and a variety of other creatures. —Jack Tamisiea, Scientific American, 2 Nov. 2023

The good reefs had 80 percent coral cover, really vibrant and colorful and bright. —Catrin Einhorn Thea Traff, New York Times, 26 Oct. 2023

And if air temperatures rise by 2 degrees Celsius, reefs will decline by 99 percent. —Margaret Osborne, Smithsonian Magazine, 30 Aug. 2023

But scientists say seaweed removal is a low-cost, nontechnical method that can significantly improve reef health. —Cameron Pugh, The Christian Science Monitor, 30 Oct. 2023

The reef site will be one of 25 artificial reefs managed by the DMF. —Julia Jacobo, ABC News, 26 Oct. 2023

On the Caribbean island of Bonaire, visitors not only witness the beauty of the reefs but can also help improve their health. —Elaine Glusac, Travel + Leisure, 16 Oct. 2023

Over the past two decades, China has occupied a number of obscure reefs and atolls far from its shoreline across the South China Sea, building up military installations, including runways and ports. —Kathleen Magramo, CNN, 4 Oct. 2023

The impact of land-dwelling rats on islands is so profound that even nearby reef fish can feel it after the rodents alter the flow of nutrients into the ocean. —Dino Grandoni, Anchorage Daily News, 5 Sep. 2023

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Word History

Etymology

Noun (1)

Middle English riff, from Old Norse rif; probably akin to Old Norse rīfa to rend — more at rive

Noun (2)

Dutch rif, from Middle Dutch, from Old Norse, literally rib; akin to Old English ribb rib — more at rib

First Known Use

Noun (1)

14th century, in the meaning defined at sense 1

Verb

1670, in the meaning defined at transitive sense 1

Noun (2)

1584, in the meaning defined at sense 1a

Phrases Containing reef

• reef knot
• coral reef
• whitetip reef shark
• barrier reef

• reef knot
• coral reef
• whitetip reef shark
• barrier reef

Kids Definition

reef

1 of 3 noun

ˈrēf 

1

: a part of a sail taken in or let out in regulating size

2

: the reduction in sail area made by reefing

reef

2 of 3 verb

: to reduce the area of (a sail) by rolling or folding a portion

reef

3 of 3 noun

: a chain of rocks or coral or a ridge of sand at or near the surface of water

Etymology

Noun

Middle English riff "reef of a sail"; of Norse origin

Noun

from Dutch rif "reef of rocks or sand"; of Scandinavian origin