Encyclopedia
Admission with Attribution
j) "reservation" means a unilateral statement, in any formulation and under any denomination, made by a State at the time of signature, ratification, acceptance or approval of a treaty or accession thereto, or at the time of notification of succession in respect of a treaty, whereby it seeks to exclude or modify the legal effect of certain provisions of the treaty in their application to that State;
Source: Vienna Convention on the Succession of States in Respect of Treaties