Communications from dining room taking a long time (8)
I believe the answer is:
messages
'communications' is the definition.
(I know this)
'dining room taking a long time' is the wordplay.
'dining room' becomes 'mess' (mess is a kind of dining room).
'taking' means one lot of letters go next to another.
'a long time' becomes 'ages' (ages can mean a very long time).
'mess'+'ages'='MESSAGES'
'from' is the link.
(Other definitions for messages that I've seen before include "Communications, written, spoken or signalled" , "Notes" , "Pieces of information carried from one person to another" , "Communications or errands" , "Communications, written, spoken or signaled" .)