ISO 3166 is a standard developed by the International Organization for Standardization (ISO) that defines codes for the names of countries, dependent territories, and special areas of geographical interest. It provides a set of two-letter (alpha-2), three-letter (alpha-3), and numeric codes to uniquely identify each location. For example, the code for the United States is US in alpha-2 and USA in alpha-3. This standard is widely used in various fields, including international shipping, data processing, and travel. By using ISO 3166 codes, organizations can ensure clear communication and avoid confusion when referring to different countries and regions around the world.