Eight lines of verse (6)
I believe the answer is:
octave
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">eight lines of verse</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for octave that I've seen before include "Series of eight consecutive musical notes" , "Eight-note range" , "Span of eight notes" , "Interval of 12 semitones" , "Interval from one C to the next C" .)