A coastline or a seashore is the area where land meets the sea or ocean , or a line that forms the boundary between the land and the ocean or a lake . A precise line that can be called a coastline cannot be determined due to the Coastline paradox.
The term coastal zone is a region where interaction of the sea and land processes occurs. Both the terms coast and coastal are often used to describe a geographic location or region ; for example, New Zealand 's West Coast, or the East and West Coasts of the United States . Edinburgh for example is a city on the coast of Scotland .
A pelagic coast refers to a coast which fronts the open ocean , as opposed to a more sheltered coast in a gulf or bay . A shore , on the other hand , can refer to parts of land adjoining any large body of water , including oceans ( sea shore ) and lakes ( lake shore ). Similarly, the somewhat related term "[ stream bed / bank ]" refers to the land alongside or sloping down to a river (riverbank) or body of water smaller than a lake . " Bank " is also used in some parts of the world to refer to an artificial ridge of earth intended to retain the water of a river or pond ; in other places this may be called a levee .
While many scientific experts might agree on a commondefinition of the term "coast", the delineation of the extents of a coast differ according to jurisdiction , with many scientific and government authorities in various countries differing for economic and social policy reasons.