noun
signatory country; party to a treaty
Refers to a country that has formally joined a treaty. Used in diplomatic and legal contexts.
この条約の加盟国は50か国以上にのぼる。
The number of signatory countries to this treaty exceeds 50.
条約加盟国は定期的に会合を開く。
The parties to the treaty hold regular meetings.
署名国 emphasizes the act of signing a treaty, while 条約加盟国 focuses on membership after ratification or accession.
Compound of 条約 (treaty) + 加盟 (participation, affiliation) + 国 (country).