The procedure by which a nation becomes a Party to an agreement already in force between other nations.

Acceptance or Approval

The act whereby a State indicates its consent to become a Party to a treaty. Acceptance/Approval are specifically provided for in a treaty and can take the form of a letter or a standard formatprescribed by the treaty itself.


“Adoption” is the formal act by which the form and content of a proposed treaty text are established. As a general rule, the adoption of the text of a treaty takes place through the expression of the consent of the States participating in the treaty-making process.


The term “Agreement” has the same meaning as treaty. “Treaty” means an international agreement concluded between international entities (States and/or Organizations). A treaty must be, (1) a binding instrument which creates rights and obligations; (2) governed by international law; and (3) in writing, whether embodied in a single instrument or in two or more related instruments. The term treaty includes: accord, convention, covenant, charter, protocol, and pact.


“Amendment” refers to the formal alteration of treaty provisions affecting all the parties to the particular agreement. Such amendments must follow the procedure applicable in treaty making and ratification.


“Authentication” means the confirmation of the text of a treaty. Once a treaty has been authenticated, States cannot unilaterally change its provisions.


Refers to engagement pertaining to a sovereign State with one other entity, which can be a State or an international Organization. Such an association is commonly known as a bilateral relationship.

Contracting Party

A contracting Party is a State or an Intergovernmental Organization or other entity with treaty making capacity that has expressed its consent to be bound by a treaty whether or not the treaty has entered into force or whether or not it has entered into force for that State or Intergovernmental Organization.

Correction of Errors

If, after the authentication of a text, the signatory and contracting States have agreed that it contains an error, it can be corrected by initialing the corrected treaty text, by executing or exchanging an instrument containing the correction or by executing the corrected text of the whole treaty by the same procedure as in the case of the original text. If there is a depositary, the depositary must communicate the proposed corrections to all signatory and contracting States.

Definitive Signature

“Definitive signature” establishes the consent of the State to be bound by a treaty that is not subject to ratification, acceptance or approval. Most bilateral treaties dealing with more routine and less politicized matters are brought into force by definitive signature, without recourse to the procedure of ratification.


The act of withdrawal of a State or Organization by giving notice that it no longer considers itself bound by a treaty.


It is the submission ofwritten instruments of a treaty which has been concluded, which provide formal evidence of consent to be bound, and also reservations and declarations to the custodian. The deposit of the instruments of ratification, acceptance, approval or accession establishes the consent of a State to be bound by a treaty.


Depositary is the place defined by the instrument where the document is to be placed after signature by the parties. The depositary must accept all notifications and documents related to the treaty, examine whether all formal requirements are met, deposit them, register the treaty and notify all relevant acts to the parties concerned.

Entry into Force

The provisions of the treaty determine the date on which the treaty enters into force. Where the treaty does not specify a date, there is a presumption that the treaty is intended to come into force as soon as all the negotiating States have consented to be bound by the treaty. Bilateral treaties may provide for their entry into force on a particular date, upon the day of their last signature, upon exchange of the instruments of ratification or upon the exchange of notifications. In cases where multilateral treaties are involved, it is common to provide for a fixed number of States to express their consent for entry into force.

Full Powers

“Full powers” means all those powers conferred, by way of a legal document, to a person or person designated by a competent State authority, 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 of a treaty.


“Modification” refers to the variation of certain treaty provisions only as between particular parties of a treaty, while in their relation to the other parties the original treaty provisions remain applicable. If the treaty is silent on modifications, they are allowed only if the modifications do not affect the rights or obligations of the other parties to the treaty and do not contravene the object and the purpose of the treaty.


Any signatory or contracting State has the option of objecting to a reservation, if, in its opinion, the reservation is incompatible with the object and purpose of the treaty. The objecting State may further declare that its objection has the effect of precluding the entry into force of the treaty as between objecting and reserving States.


An obligation is a duty that must be carried out by a Party as according to a treaty that has been concluded.


A Party to a treaty means a State, International Organization or other entity with treaty making capacity that has expressed its consent to be bound by that treaty where that treaty has entered into force for that particular State or International Organization.


Ratification means the international act by which a Statesignifies its consent to be bound to a treaty and include acceptance, approval, and accession where the treaty so provides. In the case of bilateral treaties, ratification is usually accomplished by exchanging the requisite instruments, while in the case of multilateral treaties the usual procedure is for the depositary to collect the ratification instruments of all States, and keeping all parties informed of the situation.


Means a unilateral statement made by a State when signing, ratifying, accepting, approving or acceding to treaty, whereby it purports to exclude or to modify the legal effect of certain provisions of the treaty in the application to the State.