ADJECTIVE (3)

1. made more desirable or valuable or profitable; especially made ready for use or marketing;
- Example: "new houses are springing up on an improved tract of land near the river"
- Example: "an improved breed"

2. become or made better in quality;
- Example: "was proud of his improved grades"
- Example: "an improved viewfinder"

3. (of land) made ready for development or agriculture by clearing of trees and brush;
- Example: "improved farmlands"

The Collaborative International Dictionary of English v.0.48:

Improve \Im*prove"\, v. t. [imp. & p. p. Improved; p. pr. &
   vb. n. Improving.] [Pref. in- in + prove, in approve. See
   Approve, Prove.]
   1. To make better; to increase the value or good qualities
      of; to ameliorate by care or cultivation; as, to improve
      land. --Donne.
      [1913 Webster]

            I love not to improve the honor of the living by
            impairing that of the dead.           --Denham.
      [1913 Webster]

   2. To use or employ to good purpose; to make productive; to
      turn to profitable account; to utilize; as, to improve
      one's time; to improve his means. --Shak.
      [1913 Webster]

            We shall especially honor God by improving
            diligently the talents which God hath committed to
            us.                                   --Barrow.
      [1913 Webster]

            A hint that I do not remember to have seen opened
            and improved.                         --Addison.
      [1913 Webster]

            The court seldom fails to improve the opportunity.
                                                  --Blackstone.
      [1913 Webster]

            How doth the little busy bee
            Improve each shining hour.            --I. Watts.
      [1913 Webster]

            Those moments were diligently improved. --Gibbon.
      [1913 Webster]

            True policy, as well as good faith, in my opinion,
            binds us to improve the occasion.     --Washington.
      [1913 Webster]

   3. To advance or increase by use; to augment or add to; --
      said with reference to what is bad. [R.]
      [1913 Webster]

            We all have, I fear, . . . not a little improved the
            wretched inheritance of our ancestors. --Bp.
                                                  Porteus.

   Syn: To better; meliorate; ameliorate; advance; heighten;
        mend; correct; rectify; amend; reform.
        [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

improved \improved\ adj.
   1. advanced to a more desirable or valuable or excellent
      state. Opposite of unimproved. [Narrower terms: built,
      reinforced; cleared, tilled ; {developed; grade ;
      {graded, graveled ] Also See: {restored.
      [WordNet 1.5]

   2. changed for the better; as, her improved behavior.

   Syn: amended.
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

improved
    adj 1: made more desirable or valuable or profitable; especially
           made ready for use or marketing; "new houses are
           springing up on an improved tract of land near the
           river"; "an improved breed" [ant: unimproved]
    2: become or made better in quality; "was proud of his improved
       grades"; "an improved viewfinder"
    3: (of land) made ready for development or agriculture by
       clearing of trees and brush; "improved farmlands"

Moby Thesaurus II by Grady Ward, 1.0:

40 Moby Thesaurus words for "improved":
   advanced, altered, ameliorated, beautified, better, bettered,
   changeable, changed, civilized, converted, cultivated, cultured,
   degenerate, developed, deviant, divergent, educated, embellished,
   enhanced, enriched, metamorphosed, metastasized, modified, mutant,
   perfected, polished, qualified, rebuilt, refined, reformed,
   renewed, revived, revolutionary, subversive, transfigured,
   transformed, translated, transmuted, unmitigated, worse