beach - shore - coast
A beach is an area along the edge of a sea, lake, or wide river that is covered with sand or small stones. You can relax or play on a beach, or use it as a place to swim from.
He walked along the beach.
Children were building sandcastles on the beach.
Shore is a more general word for the land along the edge of a sea, lake, or wide river.
He swam towards the shore.
The coast is the border between the land and the sea, or the part of a country that is next to the sea.
We stayed in a small village on the west coast of Scotland.
There are industrial cities along the coast.