Residue is a related term of grounds.
In legal|lang=en terms the difference between residue and grounds
is that
residue is (legal) whatever property or effects are left in an estate after payment of all debts, other charges and deduction of what is specifically bequeathed by the testator while
grounds is (legal) basis or justification for something, as in "
grounds for divorce".
As nouns the difference between residue and grounds
is that
residue is whatever remains after something else has been removed while
grounds is (legal) basis or justification for something, as in "
grounds for divorce" or
grounds can be (plural only) the sediment at the bottom of a liquid, or from which a liquid has been filtered (as in coffee grounds).