what is middleware

from http://en.wikipedia.org/wiki/Middleware

In computing, middleware consists of software agents acting as an intermediary between different application components. It is used most often to support complex, distributed applications. The software agents involved may be one or many.

The ObjectWeb consortium gives the following definition of middleware: "In a distributed computing system, middleware is defined as the software layer that lies between the operating system and the applications on each site of the system."