The internet is a very large group of computers. They are joined together so they can talk to each other. Some are joined by cables. Some use wireless signals, such as Wi-Fi.

Open a website, and your device asks a server. The server sends the page back. A server is a computer. It stores websites and apps. It gives them to other computers that ask.

A data center is a building or room. It holds many servers. It holds the equipment that joins them too. You may hear of the cloud. It is not in the sky. It means using servers in data centers through the internet.

Each device on the internet has its own address made of numbers. It is called an IP address. It is like a street address. It says where a device can be found. One kind has four numbers with dots, like 142.250.190.78.

The Domain Name System works like an address book for websites. Type a website name, and DNS finds the IP address of the server where the website lives. Domain names are easier to remember than long strings of numbers.

Messages cross the internet in small pieces called packets. Each one is like an envelope. It holds a piece of the message. It has a label with the sender, the receiver and its number.

The pieces can arrive out of order. The computer that gets them puts them back in order. A piece may get lost or damaged. Then it can ask for just that piece again. It does not ask for the whole file.

The web and the internet are not the same. The internet is the network. The web is one service that runs on it. Email is another service built on top of the internet.

As of November 2026, almost all the data between countries goes through cables laid on the sea floor.

Words to know

• server: gives out pages
• packets: small pieces
• wireless: without cables
• cloud: servers online
• address: where something is