The Internet is a global network of interconnected computer networks that use the Internet Protocol Suite (TCP/IP) to communicate with each other. It is a "network of networks" that consists of millions of private, public, academic, business, and government networks of local to global scope, linked by a broad array of electronic, wireless, and optical networking technologies.

Here are some key aspects of the Internet:

• Global Network: It spans across the world, connecting devices and networks in almost every country.
• Packet Switching: Data is broken down into packets that are routed independently from source to destination.
• TCP/IP: The Internet Protocol Suite (TCP/IP) governs how data is transmitted, routed, and received.
• Diverse Technologies: It uses a variety of technologies including fiber optics, wireless communication, and traditional copper wires.
• Decentralized: No single entity controls the Internet. It operates through distributed governance and technology standards.

The Internet facilitates various services such as the World Wide Web (WWW), email, file sharing, online gaming, e-commerce, social networking, and more. It has become an indispensable tool for communication, information, education, entertainment, and business.

Source: Internet Society - What is the Internet?