Second-largest Great Lake (5)
I believe the answer is:
huron
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">second-largest great lake</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for huron that I've seen before include "Great Lake" , "Second largest of the Great Lakes" , "N. American lake" , "One of the Great Lakes of North America" .)