Sea snail (5)
I believe the answer is:
whelk
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">sea snail</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for whelk that I've seen before include "Edible marine snail" , "Marine gastropod mollusc" , "Edible mollusc" , "Spiral-shelled mollusc" , "Mollusc with pointed shell" .)