Difference between River and River Basin - Testbook.com

River:

A river is a natural flowing watercourse, usually freshwater, running towards an ocean, sea, lake or another river. It's a significant amount of water that moves in a channel due to the force of gravity. Rivers can be various sizes – they could be vast and deep, or they might be so shallow that you could easily cross them on foot.

River basin:

In contrast, a river basin, or catchment area, is the land that water flows across or under on its way to a river. It encompasses the entire land drained by a river and its tributaries. Smaller watersheds form part of a river basin. Each tiny stream or tributary has its watershed, which eventually drains into more substantial bodies of water like rivers, ponds, wetlands, or lakes. These, in turn, are all components of a river basin.

Further Reading:

• What are the Parts of a River Called?
• The Major Indian River Systems