A cay ( or ), 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).

Çay is a town and district of Afyonkarahisar Province in the Aegean region of Turkey. the mayor is Ali Yakut (AKP).

A cay is a small, low-elevation, sandy island on the surface of a coral reef.