The process of making or becoming better
betterment, amelioration, melioration, rectification, change, amendment, alteration, reformation, progression, advance, advancement, development, refinement, growth, rise, reclamation, civilization, gain, cultivation, progressiveness, increase, enrichment, promotion, recovery, recuperation, healing, regeneration, furtherance, renovation, modernization, remodeling, refurbishment, repair, reorganization, reform, emendation, revision, elaboration, enhancement, elevation, preferment, ennoblement, shaking down*, getting the bugs out*; see also revision.
That which has been improved
addition, supplement, repair, extra, attachment, correction, reform, remodeling, modernization, betterment, refinement, luxury, advance, advancement, step forward, enhancement, new model, deluxe model, latest thing*, last word*; see also change 2.
The act of making better or the condition of being made better:amelioration, amendment, betterment, melioration, upgrade. See better
Steady improvement, as of an individual or a society:amelioration, betterment, development, melioration, progress. See better