1
: a part of a sail taken in or let out in regulating size
2
: reduction in sail area by reefing
reefed; reefing; reefs
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
: to reduce a sail by taking in a reef
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
Examples of reef in a Sentence
Recent Examples on the Web
Catrin Einhorn, New York Times, 16 May 2024
Wakeman suspects he was attacked by Caribbean reef sharks.
—Natalie Neysa Alund, USA TODAY, 13 May 2024
See all Example Sentences for reef 
Noun
The fourth global bleaching event is already the most widespread in any 365-day period, with 60 percent of reef areas subjected to bleaching-level heat stress.
—Catrin Einhorn, New York Times, 16 May 2024
Wakeman suspects he was attacked by Caribbean reef sharks.
—Natalie Neysa Alund, USA TODAY, 13 May 2024
See all Example Sentences for reef
These examples are programmatically compiled from various online sources to illustrate current usage of the word 'reef.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.
Dictionary Entries Near reef
Cite this Entry
“Reef.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/reef. Accessed 29 May. 2024.
Copy CitationKids Definition
reef
1 of 3 noun1
: 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
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