The part of a software architecture located "in the middle". The term
middleware is used for widely varying things, so try to avoid it.
Generally, it can mean anything between (but not including) the operating system and the applications. Therefore an entity that
provides processor scheduling is as less middleware as is your word
processor. Middleware provides services to applications for a specific problem area. This area is currently often distributed
systems with things like CORBA, COM, RMI, Jini called middleware. The
write-up above contains more areas and services.