The throughflow is the flow of water in the soil sideways, towards the river (sideways movement of water).

The river discharge is the amount of water that flows through a river.

The source (i.e. start) of a river is where it originates, e.g. a spring or a lake.

The mouth is the end of the river where it meets the sea or a lake.

The Long Profile shows the shape of the rivers course from source to sea

Erosion happens because of decomposition (wearing away) of rocks.

Transportation is the movement of sand, silt, sediment, or anything else carried by a river, from one point to another by the river.

Deposition is when the river loses energy, and it can't carry as much load. It drops its load (material it has been carrying), starting with the largest particles. 

The load is any material transported by the river, e.g. Sand, pebbles, rock particles.

A Meander is a winding curve in a river.