WWW stands for world wide web and contrarily to what many people think, this is not the internet.
The world wide web is basically a huge collection of webpages, or URLs, that are sitting on the internet (a network of computers).
The WWW was invented by Sir Tim Berners-Lee in 1989, and the first webpage was written and launched in 1990.
In the first ever WWW page (which can be found here) Lee explains that "the WorldWideWeb (W3) is a wide-area hypermedia information retrieval initiative aiming to give universal access to a large universe of documents".
The idea behind the concept was to allow researchers and scientists to share their experiments data more easily with the wider community.
The main technologies behind the WWW are HTML, URLs and HTTP
HTML, or in its full form HyperText Markup Language, is a common coding language used in web pages all over the internet.
A URL, in its non-abbreviation form Uniform Recourse Locater, is a web resource that essentially corresponds to a file’s unique address which is available on the internet.
HTTP is the technology used to transfer files and other contents on the internet.