CORBA is the acronym for Common Object Request Broker Architecture. It was developed under the auspices of the Object Management Group (OMG). It is middleware. A CORBA-based program from any vendor, on almost any computer, operating system, programming language, and network, can interoperate with a CORBA-based program from the same or another vendor, on almost any other computer, operating system, programming language, and network.
The first service-oriented architecture for many people in the past was with the use of Object Request Brokers (ORBs) based on the CORBA specification. The CORBA specification is responsible for really increasing the awareness of service-oriented architectures.
Organization: Object Management Group
More information: CORBA page on the OMG website
More detail for the current topic: CORBA
More on the general topic: Prior Service-Oriented Architecture Specifications