1980_____United Nations — Treaty Series • Nations Unies — Recueil des Traités 333 Believing that the codification and progressive development of the law of treaties achieved in the present Convention will promote the purposes of the United Nations set forth in the Charter, namely, the maintenance of international peace and security, the development of friendly relations and the achievement of co-operation among nations, Affirming that the rules of customary international law will continue to govern questions not regulated by the provisions of the present Convention, Have agreed as follows: PART i. INTRODUCTION Article 1. SCOPE OF THE PRESENT CONVENTION The present Convention applies to treaties between States. Article 2. USE OF TERMS 1. For the purposes of the present Convention: (a) "Treaty" means an international agreement concluded between States in written form and governed by international law, whether embodied in a single instru ment or in two or more related instruments and whatever its particular designation; (b) "Ratification", "acceptance", "approval" and "accession" mean in each case the international act so named whereby a State establishes on the international plane its consent to be bound by a treaty; (c) "Full powers" means a document emanating from the competent authority of a State designating a person or persons to represent the State for negotiating, adopting or authenticating the text of a treaty, for expressing the consent of the State to be bound by a treaty, or for accomplishing any other act with respect to a treaty; (d) "Reservation" means a unilateral statement, however phrased or named, made by a State, when signing, ratifying, accepting, approving or acceding to a treaty, whereby it purports to exclude or to modify the legal effect of certain provisions of the treaty in their application to that State; (e) "Negotiating State" means a State which took part in the drawing up and adoption of the text of the treaty; (/) "Contracting State" means a State which has consented to be bound by the treaty, whether or not the treaty has entered into force; (g) "Party" means a State which has consented to be bound by the treaty and for which the treaty is in force; Qi) "Third State" means a State not a party to the treaty; (/) "International organization" means an intergovernmental organization. 2. The provisions of paragraph 1 regarding the use of terms in the present Convention are without prejudice to the use of those terms or to the meanings which may be given to them in the internal law of any State. Article 3. INTERNATIONAL AGREEMENTS NOT WITHIN THE SCOPE OF THE PRESENT CONVENTION The fact that the present Convention does not apply to international agreements concluded between States and other subjects of international law or between such other subjects of international law, or to international agreements not in written form, shall not affect: Vol. 1155, 1-18232