Famous river (4)
'famous river' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for nile that I've seen before include "River that's Blue and White" , "long-distance runner in Africa" , "Take a line to the river" , "River of eastern Africa" , "eastern flower" .)
(Other definitions for amazon that I've seen before include "woman soldier" , "Strong, well-built woman" , "Warlike female" , "S. America's longest river" , "seller on the Internet" .)
(Other definitions for tigris that I've seen before include "Flower of Baghdad" , "Euphrates companion river" , "It flows from Turkey to the Persian Gulf" , "running water" , "Great river flowing from Turkey through Iraq" .)