Object Request Broker (ORB)
The Object Request Broker (ORB) is middleware that uses the CORBA specification. The Object Request Broker or ORB takes care of all of the details involved in routing a request from client to object, and routing the response to its destination. The ORB is also the custodian of the Interface Repository (abbreviated variously IR or IFR), an OMG-standardized distributed database containing OMG IDL interface definitions.
On the client side, then, the ORB provides interface definitions from the IFR, and constructs invocations for use with the Dynamic Invocation Interface (DII). It also converts Object References between session and stringified format, and (for CORBA 2.4 and later ORBs) converts URL-format corbaloc and corbaname object references to session references.
On the server side, the ORB de-activates inactive objects, and re-activates them whenever a request comes in. CORBA supports a number of activation patterns, so that different object or component types can activate and de-activate in the way that uses resources best.
Organization: Object Management Group
More information: ORB page on the OMG website
More on the general topic: CORBA