Subgraphs and Macros are both reusable graph segments constructed with Ab Initio pre-built components.

Both Subgraphs and Macros in Ab Initio are mechanisms for creating reusable graph segments using pre-built components. Subgraphs encapsulate a portion of a graph into a reusable component, while Macros are parameterized graph templates that can be instantiated multiple times. Both promote code reuse and modular design within the Ab Initio Graph Development Environment.