Two lines of verse (7)
I believe the answer is:
couplet
'two lines of verse' is the definition.
(I've seen this before)
This is the entire clue.
(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" .)