NIST Enterprise Architecture Model (NIST EA Model) is a late-1980s reference model for enterprise architecture. It defines an enterprise architecture by the interrelationship between an enterprise's business, information, and technology environments. Developed late-1980s by the National Institute of Standards and Technology (NIST) and others, the federal government of the United States promoted this reference model in the 1990s as the foundation for enterprise architectures of individual U.S. government agencies and in the overall federal enterprise architecture.