Answer in brief.

What are ox-bow lakes?

The course of the river results in the formation of different geographical features. An oxbow lake is an important feature formed in the middle course of the river. In the middle course, the river passes through the sloping plains and valleys along with the particles and components like sand, slits, sediments, minerals and other elements. Actions of erosion and transportation take place in the middle course resulting in the bending and twisting of the river to form meanders.

With further deposition, erosion and re-deposition, the meanders become a complete circle. The river will become much narrower with a circular surface resulting in the formation of lakes. Such features are known as ox-bow lakes. Lake Chicot in the USA is the world's largest ox-bow lake.