universal postal union
specialized agency of the United Nations that aims to organize and improve postal service throughout the world and to ensure international collaboration in this area. Among the principles governing its operation as set forth in the Universal Postal Convention and the General Regulations, two of the most important were the formation of a single territory by all signatory nations for the purposes of postal communication and uniformity of postal rates and units of weight. The original agreement adopted in 1875 applied only to letter mail; other postal services, such as parcel post and international money orders, have been regulated by supplementary agreements that are binding only on signing members
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