noun.
One who is bound by signature to the terms of an agreement; specifically, a party or state bound jointly with several others by the signing of a public treaty or convention.
Pertaining to or used in sealing: as, a signatory ring.
That has signed, or signed and sealed; bound by signature and seal, as to the terms of a contract or agreement: used specifically, in the phrase signatory powers, of the sovereign parties to a general treaty or convention, as that of Paris in 1856, or that of Berlin in 1878.