A piece of topical information that appears like lightning? (9)
I believe the answer is:
newsflash
'a piece of topical information that' is the definition.
The definition and answer can be both related to communication as well as being singular nouns.
Maybe there's a link between them I don't understand?
'like lightning?' is the wordplay.
'like' becomes 'news' (I can't explain this - if you can you should give a lot more credence to this answer).
'lightning?' becomes 'flash' (lightning is a kind of flash).
'news'+'flash'='NEWSFLASH'
'appears' acts as a link.
Can you help me to learn more?
(Other definitions for newsflash that I've seen before include "Bulletin" , "Brief report" , "Dramatic announcement" .)