Pair of verse lines (7)
I believe the answer is:
couplet
'pair of verse lines' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for couplet that I've seen before include "piece of poetry" , "Pair of verse lines" , "Pair of lines in poetry" , "bit of poetry" , "Two successive lines of verse, usually rhyming" .)