https://pubs.opengroup.org/togaf-standard/architecture-content/chap05.html#tag_05_02 Architecture Building Blocks (ABBs) relate to the Architecture Continuum (see 6.4.1 Architecture Continuum), and are defined or selected as a result of the application of the ADM. 5.2.3.1 Characteristics ABBs: Capture architecture requirements; e.g., Business, Data, Application, and Technology requirements Direct and guide the development of SBBs 5.2.3.2 Specification Content ABB specifications include the following as a minimum: Fundamental functionality and attributes: semantic, unambiguous, including security capability and manageability Interfaces: chosen set, supplied Interoperability and relationship with other building blocks Dependent building blocks with required functionality and named user interfaces Map to business/organizational entities and policies