Source : Webster's Revised Unabridged Dictionary (1913)

Gilt-edge \Gilt"-edge`\, Gilt-edged \Gilt"-edged`\, a.
   1. Having a gilt edge; as, gilt-edged paper.

   2. Of the best quality; -- said of negotiable paper, etc.
      [Slang, U. S.]

Source : WordNet®

gilt-edged
     adj 1: of the highest quality or value; "gilt-edged securities";
            "gilt-edged credentials"
     2: having gilded edges as the pages of a book