A standard is "a recognized unit of comparison by which the correctness of others can be determined." Another definition is "a set of characteristics or qualities that describes features of a product, process, or service." (Source: StandardsLearn.org)
Scientific and Professional Organizations such as the ASTM, ASME, IEEE, trade organizations, and governments produce standards. In the United States, the American National Standards Institute (ANSI) coordinates many standards producing organizations. The International Organization for Standardization (ISO) is the world's largest developer and publisher of International Standards.