Two lines of verse (7)
I believe the answer is:
couplet
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">two lines of verse</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 couplet that I've seen before include "Pair of lines in poetry" , "Two lines of verse, often rhyming" , "Pair of verse lines" , "Two successive lines of verse, usually rhyming" , "piece of poetry" .)