A civil international organization established to promote standardized telecommunications systems on a worldwide basis. Common abbreviation ITU. Note: The ITU-R and the ITU-T are committees of the International Telecommunication Union (ITU). The headquarters of the International Telecommunication Union (ITU) is in Geneva, Switzerland. While older than the United Nations, the ITU is recognized by the U.N. as the specialized agency for international telecommunications issues and standards. See also  standard,  telecommunications.