A reef is a ridge or shoal of rock, coral, or similar relatively stable material lying beneath the surface of a natural body of water. [1] Many reefs result from natural, abiotic (non-living) processes such as …

Oct 19, 2023 · A reef is a ridge of material at or near the surface of the ocean. There are natural and artificial reefs. Ecosystems are sometimes classified into terrestrial, or land-based, and aquatic. This …

As coral thickets build upward on the skeletal remains of older colonies, a reef is established. Today, richly diverse coral reefs are found along tropical coastlines, on the margins of volcanic islands, and …

5 days ago · Coral reefs are some of the most diverse ecosystems in the world. Coral polyps, the animals primarily responsible for building reefs, can take many forms: large reef building colonies, …

Jun 16, 2025 · A reef is a vibrant, complex, and biologically diverse underwater ecosystem built primarily by living organisms, most notably corals. These calcium carbonate structures provide habitat, …

: a chain of rocks or coral or a ridge of sand at or near the surface of water compare atoll, barrier reef. Examples are automatically compiled from online sources to show current usage. Read More.

Add to word list a line of rocks or sand at or near the surface of the sea: a coral reef (Definition of reef from the Cambridge Academic Content Dictionary © Cambridge University Press)

REEF meaning: a long line of rocks or coral or a high area of sand near the surface of the water in the ocean

REEF definition: a ridge of rocks or sand, often of coral debris, at or near the surface of the water. See examples of reef used in a sentence.

Among the biggest and best-known are the reef systems of the Great Barrier Reef of Australia, which is around 2,300 kilometres long. The most biologically diverse reefs in the world can be found in a …