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reef1

  (rēf) pronunciation
n.
  1. A strip or ridge of rocks, sand, or coral that rises to or near the surface of a body of water.
  2. A vein of ore.

[Obsolete Dutch rif, possibly from Old Norse, ridge.]

reefy reef'y adj.
reef2 (rēf) pronunciation Nautical.
n.

A portion of a sail rolled and tied down to lessen the area exposed to the wind.

tr.v., reefed, reef·ing, reefs.
  1. To reduce the size of (a sail) by tucking in a part and tying it to or rolling it around a yard.
  2. To shorten (a topmast or bowsprit) by taking part of it in.

[Middle English riff, from Old Norse rif, ridge, reef.]


 
 

A mass or ridge of rock or rock-forming organisms in a water body, a rock trend on land or in a mine, or a rocky trend in soil. Usually the term reef means a rocky menace to navigation, within 6 fathoms (11 m) of the water surface. Various kinds of calcium carbonate–secreting animals and plants create biogenic, or organic, reefs throughout the warmer seas. Most biogenic reefs are made of corals and associated organisms, but some entire reefs and important parts of others consist mainly of lime-secreting algae, hydrozoans, annelids, oysters, or sponges. See also Algae; Scleractinia.

The term fringing reef refers to a coral or other biogenic reef that fringes the edge of theland. A barrier reef ordinarily made of corals or other organisms parallels the shore at the seaward side of a natural lagoon. An atoll is an annular coral reef that surrounds a lagoon. See also Atoll.


 

n. each of the several strips across a sail that can be taken in or rolled up to reduce the area exposed to the wind.

v.

1. take in one or more reefs of (a sail): reefing the mainsail in strong winds.

2. shorten (a topmast or a bowsprit).

See the Introduction, Abbreviations and Pronunciation for further details.

 

Surgery involving taking in a reef of tissue, e.g. in reducing a prolapse of the preputial lining in a bull.

 
pronunciation

IN BRIEF: A submerged ridge of rock or coral near the surface of the water.

pronunciation When I was snorkeling, I watched small fish swim near the coral reef.

 
Wikipedia: reef
A reef surrounding an islet.
Enlarge
A reef surrounding an islet.

In nautical terminology, a reef is a rock, sandbar, or other feature lying beneath the surface of the water yet shallow enough to be a hazard to ships. Many reefs result from abiotic processes—deposition of sand, wave erosion planning down rock outcrops, and other natural processes—but the best-known reefs are the coral reefs of tropical waters developed through biotic processes dominated by corals and calcareous algae.

Reefs can be created artificially either by special construction or through deliberately sinking ships, but one can argue that these "reefs" are not real ones, as it is seldom the case that an artificial obstruction would be created that is a hazard to shipping. These structures are usually created to enhance physical complexity on generally featureless sand bottoms in order to attract a diverse assemblage of organisms, especially fish. Thus, "artificial reef" is a misnomer, though firmly established as the term used for man-made underwater habitat structures.

Biotic reef types

There are a number of biotic reef types, including oyster reefs, but the most massive and widely distributed are tropical coral reefs. Although corals are major contributors to the framework and bulk material comprising a coral reef, the organisms most responsible for reef growth against the constant assault from ocean waves are calcarous algae, especially, although not entirely, species of coralline algae.

Geologic reef definition

Geologists define reefs and related terms (for example, bioherm, biostrome, carbonate mound) using the factors of depositional relief, internal structure, and biotic composition. There is no consensus on one universally applicable definition. A useful definition distinguishes reefs from mounds as follows. Both are considered to be varieties of organosedimentary buildups: sedimentary features, built by the interaction of organisms and their environment, that have synoptic relief and whose biotic composition differs from that found on and beneath the surrounding sea floor. Reefs are held up by a macroscopic skeletal framework. Coral reefs are an excellent example of this kind. Corals and calcareous algae grow on top of one another and form a three-dimensional framework that is modified in various ways by other organisms and inorganic processes. By contrast, mounds lack a macroscopic skeletal framework. Mounds are built by microorganisms or by organisms that don't grow a skeletal framework. A microbial mound might be built exclusively or primarily by cyanobacteria. Excellent examples of biostromes formed by cyanobacteria occur in the Great Salt Lake of Utah (USA), and in Shark Bay, Western Australia.

Cyanobacteria do not have skeletons and individuals are microscopic. Cyanobacteria encourage the precipitation or accumulation of calcium carbonate and can produce compositionally distinct sediment bodies that have relief on the seafloor. Cyanobacterial mounds were most abundant before the evolution of shelly macroscopic organisms, but they still exist today (stromatolites are microbial mounds with a laminated internal structure). Bryozoans and crinoids, common contributors to marine sediments during the Mississippian (for example), produced a very different kind of mound. Bryozoans are small and the skeletons of crinoids disintegrate. However, bryozoan and crinoid meadows can persist over time and produce compositionally distinct bodies of sediment with depositional relief.

Geologic reef structures

Ancient reefs buried within stratigraphic sections are of considerable interest to geologists because they provide paleo-environmental information about the location in Earth's history. In addition, reef structures within a sequence of sedimentary rocks provide a discontinuity which may serve as a trap or conduit for fossil fuels or mineralizing fluids to form petroleum or ore deposits. Corals, including some major extinct groups Rugosa and Tabulata, have been important reef builders through much of the Phanerozoic since the Ordovician period. However, other organism groups, such as calcifying algae, especially members of the red algae Rhodophyta, mollusks (especially the rudist bivalves during the Cretaceous period) have created massive structures at various times. During the Cambrian period, the conical or tubular skeletons of Archaeocyatha,an extinct group of uncertain affinities (possibly sponges), built reefs. Other groups, such as the Bryozoa have been important interstitial organisms, living between the framework builders. The corals which build reefs today, the Scleractinia, arose after the Permian-Triassic extinction that wiped out the earlier rugose corals (as well as many other groups), and became increasingly important reef builders throughout the Mesozoic Era. They may have arisen from a rugose coral ancestor. Rugose corals built their skeletons of calcite and have a different symmetry from that of the scleractinian corals, whose skeletons are aragonite. However, there are some unusual examples of well preserved aragonitic rugose corals in the late Permian. In addition, calcite has been reported in the initial post-larval calcification in a few scleractinian corals. Nevertheless, scleractinian corals (which arose in the middle Triassic) may have arisen from a non-calcifying ancestor independent of the rugosan corals (which disappeared in the late Permian).

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Translations: Translations for: Reef

Dansk (Danish)
1.
n. - rev, åre

2.
n. - reb
v. tr. - rebe (sejl), mindske (sejl)

3.

idioms:

  • reef knot    råbåndsknob, rebeknob

Nederlands (Dutch)
klip, rif, reef, gevaarlijke hindernis, ertslaag in gesteente, reven

Français (French)
1.
n. - récif, écueil, (fig) écueil

2.
n. - (Naut) ris
v. tr. - prendre un ris

3.

idioms:

  • reef knot    n¯ud plat

Deutsch (German)
1.
n. - Riff

2.
n. - (mar.) Reff
v. - reffen

3.

idioms:

  • reef knot    Kreuzknoten, Reffknoten

Ελληνική (Greek)
n. - (ναυτ.) ξέρα, ύφαλος
v. - (ναυτ.) μουδάρω, σειροδετώ

idioms:

  • reef knot    σταυρόκομπος

Italiano (Italian)
scogliera, barriera

idioms:

  • reef knot    nodo piano

Português (Portuguese)
n. - recife (m)
v. - rizar

idioms:

  • reef knot    nó direito (m)

Русский (Russian)
риф

idioms:

  • reef knot    рифовый узел

Español (Spanish)
1.
n. - arrecife, escollo, filón, veta

2.
n. - (mar) parte de una vela que se recoge con una faja de rizos
v. tr. - (mar) reducir el tamaño de una vela

3.

idioms:

  • reef knot    nudo de rizo, nudo cruzado

Svenska (Swedish)
n. - (korall-)rev, (sjö) rev
v. - reva (segel)

中文(简体) (Chinese (Simplified))
1. 礁, 礁脉, 暗礁, 沙洲, 矿脉

idioms:

  • reef knot    方结

2. 缩帆部, 叠帆部, 缩, 叠卷, 收进

中文(繁體) (Chinese (Traditional))
1.
n. - 礁, 礁脈, 暗礁, 沙洲, 礦脈

idioms:

  • reef knot    方結

2.
n. - 縮帆部, 疊帆部
v. tr. - 縮, 疊捲, 收進

한국어 (Korean)
1.
n. - 암초, 모래톱, 광맥, 장애물

2.
n. - (배의) 축범부
v. tr. - 축범하다, 짧게 하다

3. 피부[각질]의 일어남

idioms:

  • reef knot    맞매듭, 옭매듭

日本語 (Japanese)
n. - 礁, 暗礁, リーフ, 鉱脈, 縮帆部, 岩礁, 砂州
v. - 縮める, 短くする, 縮帆する

idioms:

  • reef knot    本結び

العربيه (Arabic)
‏(الاسم) ثنيه الشراع, نقص في ثنيه الذراع (فعل) يخفض الساريه‏

עברית (Hebrew)
n. - ‮שונית, שרטון‬
n. - ‮קצה המפרש, קפל המפרש‬
v. tr. - ‮גולל קפל המפרש, קיפל חלק המפרש‬
reef knot - ‮קשר מרובע, קשר שטוח, קשר כפול‬


 
 

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Dictionary. The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2007. Published by Houghton Mifflin Company. All rights reserved.  Read more
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US Military Dictionary. The Oxford Essential Dictionary of the U.S. Military. Copyright © 2001, 2002 by Oxford University Press, Inc. All rights reserved.  Read more
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