It signifies death of Dickens's little girl on the radio (5)
I believe the answer is:
knell
'it signifies death' is the definition.
(as in a bell ringing a death knell)
'dickens's little girl on the radio' is the wordplay.
'dickens's little girl' becomes 'Nell' (Little Nell, character in The Old Curiosity Shop).
'on the radio' indicates a 'sounds like' (homophone) clue.
'nell' is a homophone of 'KNELL'.
'of' is the link.
(Other definitions for knell that I've seen before include "Sound of tolling bell" , "it precipitates death" , "''The curfew tolls the ... of parting day'' (Thomas Gray)" , "Solemn warning" , "Solemn sound of a bell" .)