Bing found the following results
What Is Middleware? | IBM
Middleware - Wikipedia
What is middleware? - Red Hat
What is Middleware - Definition and Examples | Microsoft Azure
What is Middleware? - Middleware Explained - AWS
What is Middleware? - GeeksforGeeks
What is Middleware? | Definition from TechTarget
Middleware: What Is It, and How Does It Work? | Built In
What Middleware Is — & How It Enables Smoother Development …
Understanding middleware - Red Hat