[at-awl, -ol, -ohl, uh-tawl, uh-tol, uh-tohl] 
| a ring-shaped coral reef or a string of closely spaced small coral islands, enclosing or nearly enclosing a shallow lagoon. |
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a·toll (āt'ôl', -ŏl', ā'tôl', ā'tŏl')  (click for larger image in new window) n. A ringlike coral island and reef that nearly or entirely encloses a lagoon. [Maldivean atolu; probably akin to Sinhalese ätul, interior (from the interior lagoon), probably from Sanskrit *antala-, interior, variant of antara-; see en in Indo-European roots.] |
A coral island that surrounds a lagoon. (See coral reef.)