What is the opposite of entropy?
Negative entropy? We know it's NOT "order".
Entropy is defined as the amount of energy dispersal present in a system. The more motion in the system, the more entropy it has... so I suppose an "opposite" thing to entropy is a measure of energy condensation...
But that is really just the opposite sign of entropy... If you want to be facetious, you could define a new state function
#Sigma = -S#
#DeltaSigma = -DeltaS#