Part of a poem (6)
I believe the answer is:
stanza
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">part of a poem</span>' is the definition.<br/ ><span class="explanation-format__explanation">('stanza' is part of 'poem')</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for stanza that I've seen before include "Unit of a poem" , "Fixed number of lines of verse" , "piece by poet" , "Lines forming a unit of verse" , "Verse of poem" .)