We don't hear the term "World Wide Web" (WWW or www) or the shortened "Web" used to mean the Internet (contraction of interconnected network) as a whole much any more. We do hear a lot about websites, web content and other usages of the term.
The Internet is the enormous network of computers that are all connected together, and the Web is a collection of webpages found on this network. Web resources are identified by a Uniform Resource Locators (URL), such as https://www.serendipity35.net.
The first and oldest (1985) registered .com domain name on the Internet is http://symbolics.com - now home to the Big Internet Museum. In 1985, there were 6 registered domains on the web; by 1992, there were about 15,000. After that, the web boomed and by 2010, there were 84 million separate domains. Today, it is more than 330 million.
Tim Berners-Lee invented the World Wide Web in 1989 and wrote the first web browser in 1990 while employed at CERN. The first web browser, called WorldWideWeb, was invented in 1990 by Berners-Lee who then recruited Nicola Pellow to write the Line Mode Browser, which displayed web pages on dumb terminals. That browser was released outside CERN in 1991 to other research institutions.
1993 saw the release of Mosaic, credited as "the world's first popular browser" with its innovation of a graphical interface. Browsers certainly made the Internet boom of the 1990s happen. Marc Andreessen was the leader of the Mosaic team, but started his own company, Netscape, which released the Netscape Navigator browser in 1994 which then overtook Mosaic (which it was based one) as the most popular browser.
The World Wide Web is the way almost all of us interact on the Internet, though it is possible to access and use the web without a browser and that is how it is used by many research institutions.
I have assigned students as a research topic the forerunners of the Internet and the Web. Berners-Lee is the start of the Web, but we can find people and concepts that precede it.
Considering the concept of the web, one person you will find goes back to 1934. Belgian lawyer and librarian Paul Otlet came to the idea that the physical wires and radio waves that were then the high tech that was connecting the world could be used for more than just entertainment.
His concept was of a “mechanical, collective brain.” My students who chose Otlet saw connections from his work to today's work on web infrastructures such as the semantic Web and browsers. Some consider Otlet to be the father of information science .