An individual or firm acting as a middleman between librarian and publisher in the acquistion of material. [Computer and Info
rmation Sciences] 
n., In the client-server model, the part of the system that performs information preparation and exchange on behalf of a client or
server. Especially in the phrase "intelligent agent" it implies some kind of automatic process which can communicate with other
agents to perform some collective task on behalf of one or more humans. [Computer and Information Sciences] 