to convoy is a form of:

Indorsement



Same as: endorsement
ENGLISH MEANING
noun
1.
The act of writing on the back of a note, bill, or other written instrument.
2.
That which is written on the back of a note, bill, or other paper, as a name, an order for, or a receipt of, payment, or the return of an officer, etc.; a writing, usually upon the back, but sometimes on the face, of a negotiable instrument, by which the property therein is assigned and transferred.
3.
Sanction, support, or approval; as, the indorsement of a rumor, an opinion, a course, conduct.