/ ˈsɪgnətri; NAmE -tɔːri/ noun
( pl. -ies ) signatory (to / of sth) ( formal ) a person, a country or an organization that has signed an official agreement :
a signatory of the Declaration of Independence
Many countries are signatories to / of the Berne Convention.
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WORD ORIGIN
late 19th cent.: from Latin signatorius of sealing, from signat- marked (with a cross), from the verb signare .