Improvement

n.
  1. The act of improving; advancement or growth; promotion in desirable qualities; progress toward what is better; melioration; as, the improvement of the mind, of land, roads, etc.
  2. The act of making profitable use or applicaton of anything, or the state of being profitably employed; a turning to good account; practical application, as of a doctrine, principle, or theory, stated in a discourse.
  3. The state of being improved; betterment; advance; also, that which is improved; as, the new edition is an improvement on the old.
  4. Increase; growth; progress; advance.
  5. (Patent Laws) A useful addition to, or modification of, a machine, manufacture, or composition.