North America's second-largest lake (5)
I believe the answer is:
huron
'north america's second-largest lake' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for huron that I've seen before include "N. American lake" , "Second largest of the Great Lakes" , "Great Lake" , "One of the Great Lakes of North America" .)