Frost's heard in kids' verses (6)
I believe the answer is:
rhymes
'verses' is the definition.
(I know this)
'frost's heard in kids'' is the wordplay.
'frost' becomes 'rime' (rime is frost by freezing water vapour).
'heard' indicates a 'sounds like' (homophone) clue.
'in kids'' becomes 's' (I can't explain this - if you can you should give a lot more credence to this answer).
'rime' sounds like 'rhyme'.
'rhyme'+'s'='RHYMES'
Can you help me to learn more?
(Other definitions for rhymes that I've seen before include "Pieces of verse" , "Short poems" , "Nursery . . . . . . are simple ditties for children" , "Similar sounds at the ends of lines of poetry" , "Verses with same-sounding ends of lines" .)