The world wide web isn’t the same thing as the internet. The internet is a network of computer networks, allowing your home network to INTERcommunicate (pls be a word so I don’t look stupid) with your ISP’s NETwork and in turn a globally interconnected network of computers. The world wide web is specifically a type of thing communicated over the internet. Don’t 100% remember what counts as a webpage but I’m going to guess the wikipedia url and if I got it right then I’ll have saved you looking it up yourself. IIRC it’s just meant to be human-readable HyperTextMarkupLanguage (HTML) pages that you can view in your browser without having to download a file to your computer. Downloading a file is something you might do on an FileTransportProtocol website (ftp.example.com vs www.example.com).

The thing is, after everything I’ve said, it basically doesn’t matter because in case you haven’t noticed, lots of, if not most, websites omit the www. subdomain from their url. The reason for this is just because almost everyone who used the internet only cares about the web. Only very specific domains and users will communicate using an ftp, imap, git, etc subdomain. Not to say these types of sites and protocols aren’t widely used, just that for eg imap, you’re much more likely to go to a website like gmail.com, outlook.com, proton.me, etc (all of which are websites but ommit the www.) and then you will access the imap part of those sites via the website.

The only part of this comment that I’m reasonably confident I didn’t get wrong is how little the difference between internet and web matters today, because almost every single time I went to talk about a non www site, I started writing “website” (instead of domain, site, url etc) and had to delete it to write something else instead.