Frost narrated a piece of poetry (5)
I believe the answer is:
rhyme
'a piece of poetry' is the definition.
(I've seen this before)
'frost narrated' is the wordplay.
'frost' becomes 'rime' (rime is frost formed by freezing water vapour).
'narrated' indicates a 'sounds like' (homophone) clue.
'rime' is a homophone of 'RHYME'.
(Other definitions for rhyme that I've seen before include "Bit of poetry" , "Sound correspondence" , "Poe's was sort of Runic" , "Have the same final sound - poetry" , "Short poem" .)