Means of weighing what's left over (7)
I believe the answer is:
balance
'means' is the definition.
(thesaurus)
I don't understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for balance that I've seen before include "Equilibrium or symmetry" , "It weighs - the remainder" , "Libra - amount in account" , "Weighing apparatus" , "Equilibrium or steady position" .)