Word Origins of Atoll, Beach, Beach Cusp, Beachline, Beach Pool, Beach Ridge - Coastal Features, Processes

In the current alphabetic series of terms relating to coastal features and processes, here are atoll, beach, beach cusp, beachline, beach pool, and beach ridge.

Atoll
The English word atoll comes from atolu in Divehi, an Indo-Aryan language of the Maldives, a group of 19 clusters of coral islands in the Indian Ocean.

An atoll is a coral reef enclosing a lagoon and forming an island.

Atolls consist of closed ribbons of reef that may or may not be circular in shape. Some atolls are very small, but others are miles in width. In a large atoll, the enclosed lagoon may reach a depth of more 160 feet.

Most of the reef in an atoll is usually beneath the surface of the water. On top of the submerged reef are usually low, flat islands or continuous strips of low, flat land.

Many well-known islands are atolls. The Maldives themselves are an example.

Two gigantic chains of coral atolls constitute the Marshall Islands, an island country in the central Pacific Ocean. The chains lie 125 miles apart and extend about 800 miles in length.

Part of the Marshall Islands is Bikini, an atoll whose lagoon is 21.5 miles long and 11 miles across. Bikini became famous during the 1940s and 1950s because of the atomic testing done there by the United States.

Wake Island, well-known for the World War II battles there, is a central Pacific Ocean atoll. It consists of three coral islets that surround a lagoon.

Many of the islands in Polynesia are atolls.

Beach
The word beach is of unknown origin.

It denotes several different kinds of coastal features, mainly these: (1) shore pebbles, that is, shingle, coarse rounded alluvial material similar to, but usually a little bigger than, ordinary gravel; (2) a gently sloping shore covered by sand, shingle, or larger rock fragments; (3) the deposit itself of such sand, shingle, or rock fragments along a shore; and (4) a seashore area in general.

Beaches are categorized in various ways. A common method describes three basic kinds of beaches. One type of beach occurs as a sediment strip resulting from rocky or cliffy areas along the coast. Another beach is the familiar outer margin of a marine plain. The third kind of beach consists of barriers, that is, narrow sandy offshore islands that are built up by the action of waves, currents, and wind and that run parallel to the coast, sometimes for dozens or even hundreds of miles.

Here are some familiar coastal terms using the word beach.

Beach cusp: a sand and rock deposit that wave action has formed into a point that projects toward the sea along a coast.

Beachline: a shoreline, especially one marked by a series of well-developed beaches.

Beach pool: a pool of water between two beaches or two beach ridges.

Beach ridge: a ridge of sand and shingle built up along a beach by wave action.
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Encyclopaedia Britannica Ready Reference 2004. CD-ROM. Encyclopaedia Britannica, 2004.

Merriam-Webster's Collegiate Dictionary. 11th ed. Springfield, Mass.: Merriam-Webster, 2006.

Merriam-Webster's Geographical Dictionary. 3rd ed. Springfield, Mass.: Merriam-Webster, 2007.

The Oxford English Dictionary. 2nd ed. Oxford, England: Clarendon Press, 1989.