The word river is derived from the Latin word ‘ripa’ meaning riverbank. In ancient times, a stream of water with definite banks was called a river. According to contemporary definitions, giant streams of water without any definite banks are called rivers. Smaller streams of water are known as brooks. In the beginning of the Universe, when mountains and seas were formed, rainfall never ceased. The rainwater ran down mountains via zigzag paths and finally joined the sea. The continuous flow of water made these tracks deeper and wider. These streams of water underwent many changes and subsequently became rivers. With the passage of time, the forms of rivers have changed. Now most of the rivers originate from mountains. The water in these rivers comes from molten snow. Rains also contribute to the water flowing into the rivers. We have already learned about glaciers. We know that when glaciers move, they also form rivers. The uneven areas coming in its path are eroded and take the shape of a river. Some of the rivers are also formed from springs and lakes. A river flows very fast near its origin, but as it advances, its depth reduces and its banks become wider because of soil erosion. The flow of river becomes very slow towards its end. There is enough accumulation of soil at the point where a river meets the sea or a lake, and the place where they meet is called a delta. The river carries a lot of silt as it flows down towards the sea and the area where rivers deposit silt is generally very fertile. Many dams are constructed on rivers to collect water. This water is made to fall from a height to generate electricity and then finally it is used for irrigation purposes.