superscription

Something written above or outside something else.

The act of superscribing.

The part of a prescription that bears the Latin word recipe represented by the symbol ℞.

That which is written or engraved on the outside of or above something else; especially, an address on a letter.

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