atoll
oxford
views updated May 23 2018atoll Ring-shaped
reef of
coral enclosing a shallow
lagoon. An atoll begins as a reef surrounding a slowly subsiding island, usually volcanic. As the island sinks, the coral continues to grow upwards until eventually the island is below
sea level and only a ring of coral is left at the surface.
http://nasa.gov/Study/Maldives/maldives.html
World Encyclopedia
atoll
oxford
views updated May 08 2018atoll Ring-shaped organic
reef that encloses or almost encloses a
lagoon, and which is surrounded by the open sea. The reef may be built of
coral and/or calcareous
algae. An atoll is built on an existing structure such as an extinct, submerged volcano.
A Dictionary of Earth Sciences AILSA ALLABY and MICHAEL ALLABY
atoll
oxford
views updated Jun 27 2018atoll A ring-shaped organic
reef that encloses or almost encloses a
lagoon and which is surrounded by the open sea. The reef may be built of coral and/or calcareous algae. An atoll is built on an existing structure such as an extinct, submerged volcano.
A Dictionary of Ecology MICHAEL ALLABY
atoll
oxford
views updated May 23 2018at·oll / ˈatˌôl; ˈatˌäl; ˈāˌtôl; ˈāˌtäl/ •
n. a ring-shaped reef, island, or chain of islands formed of coral.
The Oxford Pocket Dictionary of Current English
atoll
oxford
views updated May 14 2018atoll ring-shaped coral reef enclosing a lagoon. XIX (in XVII as
atollon). — Maldive
atoḷu.
The Concise Oxford Dictionary of English Etymology T. F. HOAD
