World Wide Web, which is popularly known as www, is the network of online content that can be accessed in through internet. Originally designed in 1991 by Tim Berners-Lee, world wide web is formatted in HTML and accessed via HTTP. We also call world wide web as "the web".
As techopedia defines it:
"The World Wide Web is what most people think of as the Internet. It is all the Web pages, pictures, videos and other online content that can be accessed via a Web browser. The Internet, in contrast, is the underlying network connection that allows us to send email and access the World Wide Web."
So we can say that the world wide web is the combination of not just resources, nut the users that are using Hypertext Transfer Protocol (HTTP).
According to World Wide Web Consortium (W3C):
"The World Wide Web is the universe of network-accessible information, an embodiment of human knowledge."
Tim Berners-Lee is the director of W3C.