WordWeb Online

1. An event that occurs when something passes from one state or phase to another
   "the alteration was intended to increase sales";
   - change, modification
    
2. The act of making something different (as e.g. the size of a garment)
   - modification, adjustment
    
3. The act of revising or altering (involving reconsideration and modification)
   "it would require a drastic alteration of his opinion";
   - revision

Derived forms: alterations

Type of: change, happening, natural event, occurrence, occurrent, transformation, translation

Encyclopedia: Alteration