There are many ways that folks refer to the areas of focus where Enterprise Architecture is applied. The following list is perhaps another approach, which I have found most useful as a "reference model" to address virtually any situation (scenario) or organization. Semantics aside, it's possible to align any service model or capability model against these six disciplines.
Business Strategy covering Corporate, BU’s, and Product Management. Understanding of customer needs and their alignment with business needs (strategy), compliance, and execution planning for change.
Covers the operational processes and systems used to deliver value to customers (external – via supply chain delivery, and internal via functional areas delivering services). Includes all manner of monitoring and measurement (e.g. KPIs & metrics). Includes integration with partners and 3rd party providers (data, assets, and services).
Data Management across the information lifecycle (from the point of capture, how it’s warehoused, extracted, and consumed). Includes data architecture, data security (includes data quality). Covers both tacit and explicit content, information, and knowledge.
Automation of all function points, business rules, processes involved in delivering services to customers (internal & ext.).
All computing infrastructure, environments, systems, structures, data storage, mobile and remote computing equipment (including 3rd party providers) involved in supporting computing, telephony, and communications.
All systems, structures, processes, and data associated with planning, executing, and implementing change.