thumb|[[Heron Island (Queensland)|Heron Island, Australia]]
A cay ( ), also spelled caye or key, is a small, low-elevation, sandy island on the surface of a coral reef. Cays occur in tropical environments throughout the Pacific, Atlantic, and Indian oceans, including in the Caribbean and on the Great Barrier Reef and Belize Barrier Reef.
Etymology
The Lucayan word for "island", , became in Spanish and "cay" in English (spelled "key" in American English).
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