A new day, before long, brings about much of the same (3,2,2)
I believe the answer is:
and so on
'about much of the same' is the definition.
I can't tell whether this definition defines the answer.
'a new day before long' is the wordplay.
'new' becomes 'n' (common abbreviation eg NT for New Testament).
'day' becomes 'd' (abbreviation for day).
'before long' becomes 'soon' (synonyms).
'a'+'n'+'d'+'soon'='AND SO ON'
'brings' acts as a link.
Can you help me to learn more?
(Other definitions for and so on that I've seen before include "I say no more" , "Etc - in English and in full" , "Etc. (3.2.2)" , "Continuing in the same way" , "Et cetera" .)