Orinoco, Orinoco River(noun)

a South American river 1,500 miles long; flows into the South Atlantic

Orinoco River

a great river in the NE. of South America, rises in the Parimé Mountains, and flowing westward bifurcates, the Cassiquiare channel going southward and joining the Rio Negro, the Orinoco proper continuing westward, north and east through Venezuela, and reaching the Atlantic after a course of 1500 m. by an enormous delta; it receives thousands of tributaries, but cascades half-way up stop navigation.