What is Internet? Why is it called- “Network of Networks”?

Question :

What is Internet? Why is it called- “Network of Networks”?

Sometimes referred to as a “network of networks,” the Internet is generally defined as a global network connecting millions of computers. The Internet is a global wide area network that connects computer systems across the world. 

No one actually owns the Internet, and no single person or organization controls the Internet entirely. The Internet is more of a concept than an actual tangible entity, and it relies on a physical infrastructure that connects networks to other networks. This physical infrastructure is what we call the world wide mesh of telecom towers, OFC lines, switches, routers, gateways etc.