Both the 1969 Vienna Convention and the 1986 Vienna Convention do not distinguish between the different designations of these instruments. The 1986 Vienna Convention on the Law of Treaties between States and International Organizations or between International Organizations ("1986 Vienna Convention"), which has still not entered into force, added rules for treaties with international organizations as parties. The 1969 Vienna Convention on the Law of Treaties ("1969 Vienna Convention"), which entered into force on 27 January 1980, contains rules for treaties concluded between States. Since there was a general desire to codify these customary rules, two international conventions were negotiated. Therefore, they are regarded as international customary law. These rules are the result of long practice among the States, which have accepted them as binding norms in their mutual relations.
The degree of formality chosen will depend upon the gravity of the problems dealt with and upon the political implications and intent of the parties.Īlthough these instruments differ from each other by title, they all have common features and international law has applied basically the same rules to all of these instruments. The title may follow habitual uses or may relate to the particular character or importance sought to be attributed to the instrument by its parties. The title assigned to such international instruments thus has normally no overriding legal effects. Some of the terms can easily be interchanged: an instrument that is designated "agreement" might also be called "treaty". In fact, the meaning of the terms used is variable, changing from State to State, from region to region and instrument to instrument. In spite of this diversity of terminology, no precise nomenclature exists. However, a fair number of additional terms have been employed, such as "statutes", "covenants", "accords" and others.
The terms most commonly used are the subject of this overview. Over the past centuries, state practice has developed a variety of terms to refer to international instruments by which states establish rights and obligations among themselves.
The purpose is to facilitate a general understanding of their scope and function. This introductory note seeks to provide a basic - but not an exhaustive - overview of the key terms employed in the United Nations Treaty Collection to refer to international instruments binding at international law: treaties, agreements, conventions, charters, protocols, declarations, memoranda of understanding, modus vivendi and exchange of notes. Definition of key terms used in the UN Treaty Collection