Extra jam, perhaps, is popular (10)
I believe the answer is:
widespread
'popular' is the definition.
(thesaurus)
'extra jam perhaps' is the wordplay.
'extra' becomes 'wide' (cricket term).
'jam perhaps' becomes 'spread' (jam is a type of spread).
'wide'+'spread'='WIDESPREAD'
'is' acts as a link.
(Other definitions for widespread that I've seen before include "broad" , "Extensive" , "available to lots of people" , "Generally prevalent" , "common" .)