WordWeb Online

1. The act of relieving ills and changing for the better
   - amelioration, betterment
    
2. A condition superior to an earlier condition
   "the new school represents a great melioration";
   - improvement
    
3. The linguistic process in which over a period of time a word grows more positive in connotation or more elevated in meaning

Derived forms: meliorations

Type of: condition, drift, improvement, status

Encyclopedia: Melioration