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

Colorful corals had bleached white, a sign of rising ocean temperatures that threaten reefs in Florida and worldwide. —Ashley Miznazi, Miami Herald, 11 Jan. 2025

Researchers caution that restoration alone isn’t enough to save reefs without wider action on climate change. —Erika Page, The Christian Science Monitor, 8 Jan. 2025

The reef, a fishing ground within the 230-mile Philippine economic zone, was seized by China in 2012 following a standoff between two nations. —Dan Perry, Newsweek, 3 Jan. 2025

The plan calls for pumping nearly a million cubic yards of sand from offshore deposits onto the beach, holding the sand there between two artificial headlands and building an artificial reef to protect it. —Philip Diehl, The Mercury News, 30 Dec. 2024

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

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

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