When an oxbow becomes completely cut off from the main river, it is called an

When an oxbow becomes completely cut off from the main river, it is called an oxbow lake. An oxbow lake is formed or results when an old river creates a meander, due to the river's eroding bark. After a long period of time, the meander becomes very curved, and eventually the neck of the meander becomes narrower and the river cuts through the neck during a flood, cutting off the meander and forming an oxbow lake.