\ ˈrēf How to pronounce reef (audio) \

Definition of reef

 (Entry 1 of 3)

1 : a part of a sail taken in or let out in regulating size
2 : reduction in sail area by reefing


reefed; reefing; reefs

Definition of reef (Entry 2 of 3)

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

Definition of reef (Entry 3 of 3)

1a : 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

Other Words from reef


reefable \ ˈrē-​fə-​bəl How to pronounce reefable (audio) \ adjective

Noun (2)

reefy \ ˈrē-​fē How to pronounce reefy (audio) \ adjective

First Known Use of reef

Noun (1)

14th century, in the meaning defined at sense 1


1670, in the meaning defined at transitive sense 1

Noun (2)

1584, in the meaning defined at sense 1a

History and Etymology for reef

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

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Time Traveler for reef

Time Traveler

The first known use of reef was in the 14th century

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Cite this Entry

“Reef.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/reef. Accessed 2 Jul. 2020.

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More Definitions for reef


\ ˈrēf How to pronounce reef (audio) \

Kids Definition of reef

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

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More from Merriam-Webster on reef

Thesaurus: All synonyms and antonyms for reef

Rhyming Dictionary: Words that rhyme with reef

Spanish Central: Translation of reef

Nglish: Translation of reef for Spanish Speakers

Britannica English: Translation of reef for Arabic Speakers

Britannica.com: Encyclopedia article about reef

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