superscription

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

Hovv counterfeit a coin they are vvho friends / Bear in their Superſcription (of the moſt / I vvould be underſtood) in proſperous days / They ſvvarm, but in adverſe vvithdravv their head / Not to be found, though ſought.

"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.

An editorial addition at the beginning, often indicating the authorship of a piece.

1911, Encyclopædia Britannica 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.

The act of superscribing.