\Su`per*struc"ture\, n. [Cf. F. superstructure.]
1. Any material structure or edifice built on something else;
   that which is raised on a foundation or basis; esp.
   (Arch.), all that part of a building above the basement.
   Also used figuratively.

         You have added to your natural endowments the
         superstructure of study.              --Dryden.

2. (Railway Engin.) The sleepers, and fastenings, in
   distinction from the roadbed.