Source : Webster's Revised Unabridged Dictionary (1913)

Skyscraper \Sky"scrap`er\, n.
   (a) (Naut.) (1) A skysail of a triangular form. [Rare] (2) A
       name for the one of the fancy sails alleged to have been
       sometimes set above the skysail. [Obs.]
   (b) A very tall building.
   (c) Hence, anything usually large, high, or excessive. [Slang
       or Colloq.]

Source : WordNet®

skyscraper
     n : a very tall building with many stories