The American Heritage® Dictionary of the English Language, 4th Edition
n. Any of various small marine clams of the genus Donax that are common in the coastal waters of the eastern and southern United States and have variously colored, often striped or banded shells.
n. A soft porous limestone, composed essentially of fragments of shells and coral, used as a building material.
n. Any of several small marine clams, of the species Donax variabilis, common in US coastal waters.
n. A soft form of limestone made of fragments of shells
the GNU version of the Collaborative International Dictionary of English
n. A soft, whitish, coral-like stone, formed of broken shells and corals, found in the southern United States, and used for roadbeds and for building material, as in the fort at St. Augustine, Florida.
The Century Dictionary and Cyclopedia
n. A rock made up of fragments of marine shells, slightly consolidated by pressure and infiltrated calcareous matter.
Word Usage
"Sources: Tile: coquina stone and sea glass, Bisazza"