The Amazon of South America

South America

South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...

 is the second longest river in the world and by far the largest by waterflow with an average discharge

Discharge (hydrology)

In hydrology, discharge is the volume rate of water flow, including any suspended solids , dissolved chemical species and/or biologic material , which is transported through a given cross-sectional area...

 greater than the next seven largest rivers combined (not including Madeira and Rio Negro, which are tributuaries of the Amazon). The Amazon, which has the largest drainage basin

Drainage basin

A drainage basin is an extent or an area of land where surface water from rain and melting snow or ice converges to a single point, usually the exit of the basin, where the waters join another waterbody, such as a river, lake, reservoir, estuary, wetland, sea, or ocean...

 in the world, about 7050000 square kilometres (2,722,020.2 sq mi), accounts for approximately one-fifth of the world's total river flow.

In its upper stretches, above the confluence of the Negro River, the Amazon is called Solimões

Solimões

Solimões is the name often given to early stretches of the Amazon River from the border of Brazil and Peru to its confluence with the Rio Negro.Further upstream from the border, the name of the river seems to depend on the speaker...

 in Brazil

Brazil

Brazil , officially the Federative Republic of Brazil , is the largest country in South America. It is the world's fifth largest country, both by geographical area and by population with over 192 million people...

; however, in Peru

Peru

Peru , officially the Republic of Peru , is a country in western South America. It is bordered on the north by Ecuador and Colombia, on the east by Brazil, on the southeast by Bolivia, on the south by Chile, and on the west by the Pacific Ocean....

, Colombia

Colombia

Colombia, officially the Republic of Colombia , is a unitary constitutional republic comprising thirty-two departments. The country is located in northwestern South America, bordered to the east by Venezuela and Brazil; to the south by Ecuador and Peru; to the north by the Caribbean Sea; to the...

 and Ecuador

Ecuador

Ecuador , officially the Republic of Ecuador is a representative democratic republic in South America, bordered by Colombia on the north, Peru on the east and south, and by the Pacific Ocean to the west. It is one of only two countries in South America, along with Chile, that do not have a border...

, as well as the rest of the Spanish-speaking world, the river is generally called the Amazon downstream from the confluence of the Marañón

Marañón

Marañón may refer to:* Marañón, Navarre, a town and municipality in Spain* Marañón River, in Peru* Marañón Province, in Peru* Valle del Marañón, a valley in Peru* Gregorio Marañón , Spanish physician, historian, writer and philosopher...

 and Ucayali

Ucayali

The Ucayali River arises about north of Lake Titicaca, in the Arequipa region of South America. The Amazon River takes its name close to Nauta city , in the confluence among Ucayali and Marañón rivers....

 rivers in Peru.