1. In the Open Systems Interconnection--Reference Model (OSI--RM,) a capability of a given layer, and the layers below it, that (a) is provided to the entities of the next higher layer and (b) for a given layer, is provided at the interface between the given layer and the next higher layer. 2. This term is used as a generic reference to distributed applications that provide "services" to other applications. 3. The association for a particular time of a user identification, a subject and a security clearance. ***PROPOSED ADDITION*** In Service Oriented Networks, the two basic uses of service are: a) Something of value being provided to and consumed by end-users of communications networks. It may be a specific service, such as Verizon FIOS IPTV Premier or Acme Restaurant Finder, or it may be general, such as VoIP telephony service or emergency services. B) A function that is performed by software whose output is used by some other entity. It may be, for example, a presence engine, or a routing function, or a number translation capability, or protocol interworking. ‘Service' may also refer to the software itself. A service can be turned into a Service Enabler when complemented with appropriate logic and exposure building blocks, so that it can be reused or combined by another application through well-defined functional and operational interfaces. This definition is being proposed for addition/change in the ATIS Telecom Glossary by the PRQC. If you have any objections to this acronym being added to the Telecom Glossary, please contact Paul Savitz, PRQC Committee Administrator, via email at psavitz@atis. Org to note your objection. ***