Huge mythical bird (3)
I believe the answer is:
roc
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">huge mythical bird</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 roc that I've seen before include "Huge mythical bird of prey" , "Legendary flier" , "Cor! what a fabulous bird" , "Gigantic bird of Arabian legend" , "Sinbad's giant bird" .)