Why is the Internet described as a network of networks?

The Internet is described as a "network of networks" because its architecture is designed to integrate diverse, independent computer networks into a single, cohesive global system.12

Rather than being a single, monolithic entity, the Internet relies on an open architecture that allows various local and wide-area networks to connect seamlessly. This integration is made possible by the Internet protocol suite, specifically the Transmission Control Protocol and Internet Protocol (TCP/IP). These standardized protocols act as a universal language, enabling different types of hardware, operating systems, and network infrastructures to exchange data reliably.1324

By using packet switching, the Internet breaks information into smaller units that can be routed across multiple channels and diverse network paths to reach their destination. This flexible, layered approach allows the Internet to function as a vast, interconnected web, effectively linking computers worldwide regardless of the specific underlying network technology they use.123