It's not the same as a disagreement (10)
I believe the answer is:
difference
'disagreement' is the definition.
(I know that difference is a type of disagreement)
I don't understand the rest of the clue.
Can you help me to learn more?
(Other definitions for difference that I've seen before include "Change" , "Discrimination" , "Quarrel; remainder in subtraction" , "Diversity" , "Variation" .)