Course of Nile meandering (4)
I believe the answer is:
line
'course' is the definition.
('line' can be a synonym of 'course')
'nile meandering' is the wordplay.
'meandering' is an anagram indicator.
'nile' with letters rearranged gives 'LINE'.
'of' is the link.
(Other definitions for line that I've seen before include "Family" , "cover on the inside" , "Wrinkle; phone link" , "Row; track" , "Long narrow mark" .)