An ID assigned exclusively by SAP that allows SAP customers, SAP partners and SAP to develop SAP components and products using SAP applications, without the danger of naming conflicts. (Naming conflicts can occur during transports to external SAP Systems, or when importing external products into your own systems.)
You assign objects to a namespace in the ABAP Workbench by placing the namespace prefix in front of the object name. The namespace ID begins and ends with a delimiter (“/”), and can have up to 10 characters.