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

Once docked, snorkelers will splash into the water and snorkel among turtles, rays, and schools of fish, including the blue-green Hawaiian sergeant and colorful reef triggerfish, the state fish. —Rachel Ng, AFAR Media, 7 May 2025

Tickets to Discovery Cove include meals, drinks, snorkeling in the artificial reef, and animal encounters. —Brandee Gruener, Southern Living, 30 Apr. 2025

Verb

This phase involves everything from building regulations to availability of labor locally, as well as environmental-impact assessments and bathymetric studies of the ocean floor and reefs up to 100 feet offshore. —Abby Montanez, Robb Report, 27 Apr. 2025

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

Rhymes for reef

• beef
• brief
• chief
• fief
• grief
• leaf
• lief
• reif
• seif
• sheaf
• thief
• belief

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