Filbert or cob (8)
I believe the answer is:
hazelnut
<span class="explanation-format__ClueExplanation">I believe this is a double definition.<br/ ><br/ >'<span class="explanation-format__original">filbert</span>' is the first definition.<br/ ><span class="explanation-format__explanation">(synonyms)</span><br/ ><br/ >'<span class="explanation-format__original">cob</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(I know that cob can be written as hazelnut)</span><br/ ><br/ ></span>
(Other definitions for hazelnut that I've seen before include "Cobnut or filbert" , "Filbert or cob" .)