A more thorough explanation:

Definition: A slough is either an arm of a river that is separate from the main channel or a bog, which is a place filled with deep mud.

• The Mississippi River has many sloughs that branch off from the main channel.
• The hiker got stuck in a slough and had to be rescued.
• The wetlands were filled with sloughs that provided habitats for various species of birds and fish.

The first example illustrates the first definition of slough as an arm of a river. The second example illustrates the second definition of slough as a bog or a place filled with deep mud. The third example shows how sloughs can be a part of a larger ecosystem and provide habitats for various species.