Poetry heard in prime time (5)
I believe the answer is:
rhyme
This clue is a double definition.
'poetry' is the first definition.
(rhyme is a type of poetry)
'heard in prime time' is the second definition.
('prime' and 'time' are rhymes)
(Other definitions for rhyme that I've seen before include "Poe's was sort of Runic" , "End with a similar sound" , "Nursery verse?" , "Versification (which goes with reason)" , "Similarity of word-sounds" .)