Hickory nut (5)
I believe the answer is:
pecan
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">hickory nut</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for pecan that I've seen before include "Walnut-like nut" , "Nutty type" , "Species of hickory - edible nut" , "Edible nut like a smooth walnut" , "of nuts" .)