Source : Webster's Revised Unabridged Dictionary (1913)

Superscription \Su`per*scrip"tion\, n. [L. superscriptio. See
   {Superscribe}.]
   1. The act of superscribing.

   2. That which is written or engraved on the surface, outside,
      or above something else; specifically, an address on a
      letter, envelope, or the like. --Holland.

            The superscription of his accusation was written
            over, The King of the Jews.           --Mark xv. 26.

   3. (Pharm.) That part of a prescription which contains the
      Latin word recipe (Take) or the sign ?.

Source : WordNet®

superscription
     n 1: an inscription written above something else
     2: the activity of superscribing