Atoll
noun /ˈætɒl/ — A ring-shaped coral island enclosing a lagoon — the sea's most precise geometry.
Definition
A ring-shaped reef, island, or chain of islands formed of coral, enclosing or nearly enclosing a shallow lagoon.
Beyond the definition
An atoll is one of nature's most structured forms — a ring of coral that creates its own protected interior. Darwin was fascinated by atolls: they made visible the slow work of time and biology cooperating over centuries.
Origin & history
From Dhivehi atholhu — a cluster of islands (the language of the Maldives). A word borrowed from the people of the atolls themselves — the language that named what it lived on.
Example sentences
Illustrative sentences for learning, not verified community posts or sourced quotations.
The atoll appeared on satellite images as a perfect ring — coral that had taken a thousand years to close itself.
Inside the atoll's lagoon, the water was a different blue — protected, clear, and unbelievably still.
Darwin spent months studying atolls, trying to understand how a ring of coral could form where once a mountain stood.
How to use it
This entry uses a noun. Follow the examples for articles and singular or plural forms; not every noun takes “a” or “an.”
Choose “Atoll” when the meaning fits your context: A ring-shaped reef, island, or chain of islands formed of coral, enclosing or nearly enclosing a shallow lagoon.
Synonyms
coral island, ring island, lagoon island
Antonyms
mainland, continent
Related words
Word in the Wild
See how this word appears in life, language and stories.
Illustrative sentences and imagined stories for learning — not verified sightings, interviews, or sourced quotations.
Illustrative example
Jellyfish drifting in a ring
Several jellyfish drift together in a circular, ring-like formation beneath the water's surface.
The ring-like drifting of the jellyfish provides a visual analogy for an atoll, a ring-shaped reef structure surrounding a central, contained space.
Image credit: W.carter · CC BY-SA 4.0 (license)
Resized and converted to WebP; displayed with a fitted crop.
Questions about this word
What does "Atoll" mean?
Atoll is noun meaning: A ring-shaped coral island enclosing a lagoon — the sea's most precise geometry.. A ring-shaped reef, island, or chain of islands formed of coral, enclosing or nearly enclosing a shallow lagoon.
Where does the word "Atoll" come from?
From Dhivehi atholhu — a cluster of islands (the language of the Maldives). A word borrowed from the people of the atolls themselves — the language that named what it lived on.