What is a middleware?

Middleware is software that acts as an intermediary between an operating system and software applications, especially on a network. Middleware is generally used for linking various software applications and passing data between them. Thus, It is also known as "software glue" and plumbing. For example, it can help an organization by messaging its customers, linking its payment and other systems with its customer-focused applications. Middleware enables communication and resource management for distributed applications.