The New Student's Reference Work/Atoll
Atoll (ȧ-tŏl'), the native name commonly applied in the Indian Ocean to a lagoon island, a low, usually circular reef, often composed of coral and the sand and soil washed up by the sea, and upon which a stunted vegetation grows, with an occasional palm tree a variety of shrubs. Many atolls are as much as a hundred miles in circumference, and enclose bodies of water varying from 12 to 50 fathoms; they furnish good temporary harbors, open here and there, by narrow inlets from the sea. In many cases they are inhabited by Malays. See Coral Island and Reef.