Enterprise Architecture (EA) is a discipline which has evolved to structure the business and its alignment with the IT systems. The Zachman Framework is an enterprise ontology and is a fundamental structure for Enterprise Architecture which provides a way of viewing an enterprise and its information systems from different perspectives, and showing how the components of the enterprise are related.
Enterprise Architecture is the process used by a business to make explicit representations of enterprise operations and resources, rather than relying on implicit notions or understanding in individual managers' heads.