superscription

noun3

1. •
   Something written (or engraved) on the surface, outside, or above something else; specifically, an address on a letter, envelope, etc.

   • "Dear me, Mr. Holmes. Dear me!" said this singular epistle. There was neither superscription nor signature. I laughed at the quaint message; but Holmes showed unwonted seriousness. — 1914
2. •
   An editorial addition at the beginning, often indicating the authorship of a piece.

   • By a pure error, or perhaps through a confusion in the traditions, Achish the Philistine (of Gath, 1 Sam. xxi., xxvii.), to whom David fled, is called Abimelech in the superscription to Psalm 34. — 1911
3. •
   The act of superscribing.