A coastline or seashore is the area where land meets the sea or ocean. A precise line that can be called a coastline cannot be determined due to the dynamic nature of tides. The term coastal zone can be used instead, which is a spatial zone 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 such as the east coast.
A pelagic coast is a coast which fronts the open ocean, as opposed to a more sheltered coast in a gulf or bay. A shore can refer to parts of the land which adjoin any large body of water, including oceans and lakes.