From the Paris Convention for the Protection of Industrial Property (originally dated 1883) below, it seems that IGO is defined as:
- international intergovernmental organizations of which one or more countries of the Union are members The wording in the Paris Convention (http://www.wipo.int/treaties/en/ip/paris/trtdocs_wo020.html#P155_22332) " (a) The countries of the Union agree to refuse or to invalidate the registration, and to prohibit by appropriate measures the use, without authorization by the competent authorities, either as trademarks or as elements of trademarks, of armorial bearings, flags, and other State emblems, of the countries of the Union, official signs and hallmarks indicating control and warranty adopted by them, and any imitation from a heraldic point of view. (b) The provisions of subparagraph (a), above, shall apply equally to armorial bearings, flags, other emblems, abbreviations, and names, of international intergovernmental organizations of which one or more countries of the Union are members, with the exception of armorial bearings, flags, other emblems, abbreviations, and names, that are already the subject of international agreements in force, intended to ensure their protection. (c) No country of the Union shall be required to apply the provisions of subparagraph (b), above, to the prejudice of the owners of rights acquired in good faith before the entry into force, in that country, of this Convention. The countries of the Union shall not be required to apply the said provisions when the use or registration referred to in subparagraph (a), above, is not of such a nature as to suggest to the public that a connection exists between the organization concerned and the armorial bearings, flags, emblems, abbreviations, and names, or if such use or registration is probably not of such a nature as to mislead the public as to the existence of a connection between the user and the organization." Note that "The countries to which this Convention applies constitute a Union for the protection of industrial property." Regards, Bruce Tonkin