A computer network is a system where two or more computers are connected to share data, resources, and information. It allows communication through email, messaging, video calls, and file sharing. Networks can be wired (Ethernet cables) or wireless (Wi-Fi). They are used in homes, schools, offices, and across the Internet. Main components include computers, servers, routers, switches, and communication media. Common types of networks are LAN, MAN, and WAN based on coverage area. Computer networks use protocols like TCP/IP to ensure proper and reliable data communication.