Type of duck (5)
I believe the answer is:
eider
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">type of duck</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 eider that I've seen before include "Down comes from this" , "Source of fine soft down" , "Reed I turn into a duck" , "Duck valued for its fine soft down" , "Species of duck" .)