The term River comes from latin fluvius. It is a natural continuous water stream which leads to a river, a lake or the sea. If a river leads to another, it takes the name of tributary.
Each river has a flow, which is not really constant during the year. During periods where the rains are very heavy, the flow tends to increase. On the other hand, if it does not rain enough or high temperatures, flow down and the river may dry under extreme conditions.
A river can be sustainable if the watercourse is located in areas with heavy rainfall or where the water supply is sufficient; seasonal, if it is in a region where the seasons are sufficiently differentiated and that the climate is Mediterranean; transitional, finds itself in an area where the climate is dry or desert; or allochthonous, finds itself in an arid area and its waters come other rainiest regions.
It is possible to classify the rivers according to their geomorphology. Straight rivers present a low sinuosity and have only a single channel. The rivers braided, on the other hand, have many channels and a high-capacity transport and sedimentation. Finally, the meandering rivers have strong sinuosities and a single channel.
The largest river in the world is the Amazon, whose extension is 6,800 kilometers. After him, there is the Nile, with 6.450 kilometres.
In the literary language, the word River is used to refer to what is rumored with abundance ("should be rivers of ink just to write the history of the president"). As affixing (compound words), it is used to indicate something excessive in length. The course of the narrative of the novels rivers, for example, sometimes quickly, sometimes slowly taking place.