1. Convention as a generic term: Art.38 (1) (a) of the Statute of the International Court of Justice refers to "international conventions, whether general or particular" as a source of law, apart from international customary rules and general principles of international law and - as a secondary source - judicial decisions and the teachings of the most highly qualified publicists. This generic use of the term "convention" embraces all international agreements, in the same way as does the generic term "treaty". Black letter law is also regularly referred to as "conventional law", in order to distinguish it from the other sources of international law, such as customary law or the general principles of international law. The generic term "convention" thus is synonymous with the generic term "treaty".
2. Convention as a specific term: Whereas in the last century the term "convention" was regularly employed for bilateral agreements, it now is generally used for formal multilateral treaties with a broad number of parties. Conventions are normally open for participation by the international community as a whole, or by a large number of states. Usually the instruments negotiated under the auspices of an international organization are entitled conventions (e.g. Convention on Biological Diversity of 1992, United Nations Convention on the Law of the Sea of 1982, Vienna Convention on the Law of Treaties of 1969). The same holds true for instruments adopted by an organ of an international organization (e.g. the 1951 ILO Convention concerning Equal Remuneration for Men and Women Workers for Work of Equal Value, adopted by the International Labour Conference or the 1989 Convention on the Rights of the Child, adopted by the General Assembly of the UN).https://treaties.un.org/Pages/overview.aspx?path=overview/definition/page1_en.xml