The World Wide Web (WWW) is a system of interconnected public web pages accessible through the internet. It is a collection of websites or web pages stored in web servers and connected to local computers through the internet. The WWW consists of multiple components that enable users to access various resources, documents, and web pages on the internet. These pages are the primary component or building blocks of the WWW and are linked through hyperlinks, which provide access from one specific spot in a hypertext or hypermedia document to another spot within that document or a different one. The WWW was initiated by CERN (European library for Nuclear Research) in 1989. It was developed to combine recent computer technologies, data networks, and hypertext into a user-friendly and effective global information system.

The WWW is not the same as the internet, but it is one of many applications built on top of the internet. The internet is a global network of computers that communicate with each other using standardized protocols. The WWW is a communications model or platform that enables the retrieval or exchange of information over the internet through HTTP.

The www prefix is often used in hostnames for web servers because of the long-standing practice of naming internet hosts according to the services they provide. However, the use of www is not required by any technical or policy standard, and many websites do not use it. Many established websites still use the prefix, or they employ other subdomain names such as www2, secure, or en for special purposes.