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

The soundscape mimicked the sounds of a coral reef alongside dynamic lighting intended to depict a lifeless and pale reef regenerating to become a healthy reef bursting with life. —Cat Cardenas, Variety, 10 Apr. 2025

The reefs have taken their share of ships since then, ironically making the waters around the island a diver’s paradise. —Robb Report Studio, Robb Report, 9 Apr. 2025

The massive swells are caused by the deepwater reefs, not recommended for novice surfers or swimmers. —Mariette Williams, AFAR Media, 7 Apr. 2025

Why Being Passive Is Key When Diving With Manta Rays In The Maldives The Manta Trust reported over 104,000 sightings of more than 5,500 different reef manta rays throughout 20 years in the Maldives, making the population here the largest in the world. —Emese MacZko, Forbes.com, 31 Mar. 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