signatory

noun

1. One who signs or has signed something.

   “Near-synonyms: undersigned, subscriber”

   “John Hancock is famous for being the first signatory to the American Declaration of Independence, and for writing his name large.”

   “[...] it is reported that signatories of a petition for retention of service include the Home Secretary, Mr. R. A. Butler, who resides in the neighbourhood.”

adj

1. (not-comparable)Relating to a seal; used in sealing.

   “signatory Rings”

2. (not-comparable)Signing; joining or sharing in a signature.

   “signatory powers”