The Nile River in Africa holds the title of being the longest river in the world, stretching over 6,650 kilometers (4,132 miles).

Rainfall is the primary source of water for rivers and streams, as it replenishes their flow and maintains their water levels.

Erosion is the process by which a river or stream wears away and transports sediment, shaping its channel and landscape.

A delta is a landform created by the deposition of sediment at the mouth of a river or stream, where it meets a larger body of water.

Meandering is the term used to describe the sinuous, curved path that a river or stream takes as it flows across a landscape.

The Ohio River is a tributary of the Mississippi River, joining it in Cairo, Illinois.

A watershed, also known as a catchment or basin, is the area of land that drains into a river or stream and its tributaries.

An ephemeral stream is a type of river or stream that flows only during periods of heavy rainfall or snowmelt, and is typically dry for most of the year.

The mouth of a river or stream is the point where it meets a larger body of water, such as an ocean, lake, or sea.

A karst river is a type of river or stream that flows underground through soluble rock, such as limestone or gypsum, creating unique cave systems and underground channels.

Avulsion is the term used to describe the process by which a river or stream changes its course over time, eroding and depositing sediment, often resulting in the formation of new channels.

A canyon river is a type of river or stream that flows through a deep, narrow valley with steep sides, often formed by erosion over time.

A floodplain is the area of land adjacent to a river or stream that is prone to flooding during high water levels.

A braided river is a type of river or stream that has a braided channel, with multiple channels and islands, often formed due to sediment deposition.

Incision is the term used to describe the process by which a river or stream gradually erodes its bed and banks, deepening and widening its channel.