Concerning a morning's papers (5)
I believe the answer is:
reams
'papers' is the definition.
(a ream is a large amount of paper)
'concerning a morning's' is the wordplay.
'concerning' becomes 're' (both can mean on a particular topic).
'a morning's' becomes 'ams' (as in 12:00 AM).
're'+'ams'='REAMS'
(Other definitions for reams that I've seen before include "Large quantities (of paper?)" , "Scrapes the barrel" , "Lots of paper" , "Large quantity of written matter" , "This much paperwork" .)