cosignatory
co-signatory, n ~ (of/to sth) person, state, etc signing jointly with others 连署者(人、 国家等)
The US and the former Soviet Union were co-signatories of/to the treaty. 美国和前苏联都是条约的签署国.
🗣️ 情景例句
I've had a pretty high fever since yesterday morning.