Another word for improvement
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.