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