Stay with German article for balance (9)
I believe the answer is:
remainder
'for balance' is the definition.
(I've seen this before)
'stay with german article' is the wordplay.
'stay' becomes 'remain' (synonyms).
'with' means one lot of letters go next to another.
'german article' becomes 'der' (definite article in German).
'remain'+'der'='REMAINDER'
(Other definitions for remainder that I've seen before include "Left-over" , "book going cheap" , "Dispose of unsold books cheaply" , "Scrap" , "set of unsold books" .)