Updated: 2017-12-20.

A cay is a type of island that is a low bank or reef made of accumulated sand, coral, or rock.

Usually, if the accumulated sediments are predominantly sand, it is a cay; if it is predominantly rock or gravel, it is a motu. Well-known examples are the Florida Keys and Heron Island of Australia’s Great Barrier Reef.

Cay is pronounced interchangeably like “key” or “kaye”and also spelled as “key.”

Categories: Geography Terms
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