The Internet is a network of autonomous computers linked together by wireless, cable or fiber links; devices exchange information over the network through data packets. It is governed by a set of protocols called TCP/IP.
Every Internet-enabled device understands the TCP/IP protocol. It allows these devices to electronically send, receive, interpret and describe data over the network. TCP (Transmission Control Protocol) is responsible for breaking down each data piece (web pages and messages) into smaller parts known as packets. The IP (Internet Protocol) is responsible for ensuring that data gets from the source to the destination by going through a network of routers.
Each device connected to the Internet has a unique address. The IP address is usually in the form of nnn.nnn.nnn.nnn, where n represents a number ranging from 0 to 255. If the device is connected to the Internet via an ISP (Internet Service Provider), the ISP typically assigns the device a temporary IP address that lasts the duration of a dial-up session. However, if the device is directly connected to a LAN (Local Area Network), it will be given a permanent IP address.
Despite the way in which the terms "World Wide Web" (WWW) and "Internet" are synonymously used, the two are different. The World Wide Web is simply a subset of the Internet.