from The American Heritage® Dictionary of the English Language, 4th Edition
- n. A ringlike coral island and reef that nearly or entirely encloses a lagoon.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. A type of island consisting of a ribbon reef that nearly or entirely surrounds a lagoon and supports, in most cases, one to many islets on the reef platform. Atolls have a unique geology, so not all islands with a reef and a lagoon are atolls.
from the GNU version of the Collaborative International Dictionary of English
- n. A coral island or islands, consisting of a belt of coral reef, partly submerged, surrounding a central lagoon or depression; a lagoon island.
from The Century Dictionary and Cyclopedia
- n. A coral island, consisting of a strip or ring of coral surrounding a central lagoon.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. an island consisting of a circular coral reef surrounding a lagoon
The atoll is on admiralty charts as Hikihoho, discovered by Bougainville [Louis Antoine de Bougainville, 1729-1811, French soldier and explorer, the first Frenchman to circumnavigate the world] but called Parlay after old Parlay, a wizard with pearls who never parts with a pearl and stores hundreds of ton of shell.
The ring-like shape of the atoll is the result of coral reefs building up around a former volcanic island.
The rim of the atoll is a karst structure; there is also a quantity of exposed coral rock and extensive sand dunes and rubble to the southwest.
Bassas da India (Iles Eparses): the atoll is a circular reef that sits atop a long-extinct, submerged volcano
Inside the atoll is a large lagoon with shallows and pools 1 to 5 m deep.
The landing would take them down the runway away from the concentration of Russian troops; according to the satellite photo, they would have some cover at that end of the atoll from a short run of rocks.
Below it, the atoll was a tiny bull's eye in a huge target.
Bassas da India: the atoll is a circular reef that sits atop a long-extinct, submerged volcano
When we remember that the atoll is a living thing, an organic whole, as full of life, though not so highly organised, as a tortoise, the meanest imagination must be struck with the immensity of one of the structures.
The southern group consists of seven or eight islands and islets on the atoll, which is the skeleton of what some day, according to the history of coral reefs, will be a continuous island.