Lake fed by the Detroit River (4)
I believe the answer is:
erie
'lake fed by the detroit river' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for erie that I've seen before include "Lake between Canada and the US" , "The lake sounds weird" , "Great lake in Eire" , "N. American lake" , "One of the Great Lakes" .)