Sentence:  <WSD>Negentropy</WSD> is the difference between the entropy of a system and the entropy of the same system at equilibrium (i.e., when it has its maximum possible entropy). Since entropy measures the amount of disorder, <WSD>negentropy</WSD> measures order. 
Meaning of the word marked with <WSD> tags:  The difference between the entropy of a system and the maximum possible entropy of the same system. (from 1950s)