Long heroic poem (4)
I believe the answer is:
epic
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">long heroic poem</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 epic that I've seen before include "Long poem/story" , "Long poem telling of heroic events" , "blockbuster" , "eg The Iliad" , "Confirm the truth of" .)