Also, before long, etc. (3,2,2)

I believe the answer is:

and so on

'etc' is the definition.
(I've seen this before)

'also before long' is the wordplay.
'also' becomes 'and' (I've seen this before).
'before long' becomes 'soon' (I've seen this before).
'and'+'soon'='AND SO ON'

(Other definitions for and so on that I've seen before include "Continuing in the same way" , "Etc - in English and in full" , "I say no more" , "Et cetera" , "Etc. (3.2.2)" .)

I've seen this clue in The Telegraph.

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