Address. An identifier that is a synonym for the fully qualified IPC-Process-Instance, which is a member of a DIF. An address is only unambiguous within the DIF (and assigned by the DIF).  This identifier may be assigned  to facilitate its usefulness to the operation of the DIF, i.e. location-dependent.

API-primitive. A library or system call used by an application to invoke functions, in particular IPC functions, such as requesting the allocation of IPC resources.