Albacore or bluefin (4)
I believe the answer is:
tuna
<span class="explanation-format__ClueExplanation">I believe this clue is a double definition.<br/ ><br/ >'<span class="explanation-format__original">albacore</span>' is the first definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >'<span class="explanation-format__original">bluefin</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ ></span>
(Other definitions for tuna that I've seen before include "Marine food for your strange aunt" , "Fish, often tinned" , "Large food fish" , "Large fish found in a nut" , "A fish; sounds like piano juster" .)