The coast is defined as the part of the land adjoining or near the ocean.
A coastline is properly, a line on a map indicating the disposition of a coast but the word is often used to refer to the coast itself.
The adjective, coastal describes something as being on, near to or associated with a coast.
The coast and its adjacent areas on and off shore is an important part of a local ecosystem as the mixture of fresh water and salt water in estuaries provides many nutrients for marine life.
Salt marshes and beaches also support a diversity of plants, animals, and insects crucial to the food chain.
Like the ocean which shapes them, coasts are a dynamic environment with constant change.
The earth's natural processes, particularly sea level rise, waves and various weather phenomena, have resulted in the erosion, accretion and reshaping of coasts as well as flooding and creation of continental shelves and drowned river valleys (rias).