The Business Architecture defines the business strategy, governance, organization, and key business processes.
The Data Architecture describes the structure of an organization's logical and physical data assets and data management resources.
The Application Architecture provides a blueprint for the individual applications to be deployed, their interactions, and their relationships to the core business processes of the organization.
The Technology Architecture describes the logical software and hardware capabilities that are required to support the deployment of business, data, and application services. This includes IT infrastructure, middleware, networks, communications, processing, standards, etc.