Stands for "American National Standards Institute." ANSI is a U.S.-based non-profit organization that works to develop and promote standards in the United States and around the world. By standardizing new products and technologies, ANSI both strengthens the United States' position in the global marketplace and helps ensure product integrity and safety.
ANSI was originally called the "American Engineering Standards Committee" (AESC), which was formed in 1918. The AESC worked with the American Institute of Electrical Engineers (now the IEEE) and several other organizations to develop engineering standards. In 1928, AESC was reorganized and renamed the "American Standards Association" (ASA). The ASA began to develop partnerships with global organizations, such as the ISO and helped promote U.S. standards internationally. In 1969, the ASA was renamed to ANSI. For the past several decades, ANSI has continued to promote both national and international standards.
By standardizing new technologies, ANSI helps both corporations and government agencies create compatible products and services. For example, when ANSI standardizes a specific type of hardware port, computer manufacturers can build machines with the standardized port and know it will will be compatible with third-party devices. When ANSI standardizes a file format, software developers can support the format in their programs, since information about the format is publicly available.
When a new standard is accredited by ANSI, it means that the standard has met the organization's requirements for openness, balance, and consensus. In other words, only standards that pass a due process of rigorous approval guidelines become accredited standards. This ensures that all standards accredited by ANSI are worthwhile for manufacturers and consumers alike.
Additional information about ANSI can be found at the official ANSI website.