A semantic broker is a computer service that automatically provides semantic mapper

Semantic mapper

A semantic mapper is tool or service that aids in the transformation of data elements from one namespace into another namespace. A semantic mapper is an essential component of a semantic broker and one tool that is enabled by the Semantic Web technologies....

 services. A semantic broker is frequently part of a semantic middleware

Middleware

Middleware is computer software that connects software components or people and their applications. The software consists of a set of services that allows multiple processes running on one or more machines to interact...

system that leverage semantic equivalence statements. To qualify as a semantic broker product a system must be able to automatically extract data from a message and use semantic equvalance statements to transform this into another namespace.