Vegetable gourd (6)
I believe the answer is:
marrow
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">vegetable gourd</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for marrow that I've seen before include "Soft bone tissue" , "Large gourd fruit or stuff in bone cavities" , "Connective tissue in bones" , "Oversized courgette" , "Large vegetable gourd or stuff in bones" .)