Object Request Broker

ORB -- generically, an object which provides a way of accessing services without knowing at compile time which other object in the system provides that service, somewhat like the AbstractFactoryPattern, although usually objects will register the services they provide with the ORB at runtime. You would normally only be able to request an service by interface, not by implementation. Most commonly used to refer to an implementation of CommonObjectRequestBrokerArchitecture (CORBA).