In SAP RAP (RESTful ABAP Programming Model), Service Definition is used to expose your Business Object to external applications.

It acts as a bridge between backend logic and frontend consumption, especially for SAP Fiori applications.

Key Points: ✔ Defines which data and operations are exposed ✔ Works with Business Objects and CDS Views ✔ Required before creating Service Binding ✔ Helps in building OData services