> Non-Centralisation

I imagine this term was used because it was before everything got centralized, so there was no need to "de-"centralize yet.

> client/server model

The original design of the WorldWideWeb application was a web browser and editor, which I think implies that anyone using it could run a server as easily as browsing other people's servers.

Edit: Not totally sure, but it does seem there was an HTTP server bundled with the browser/editor.

How to make a WWW server (1992) - https://www.w3.org/History/19921103-hypertext/hypertext/WWW/...

WWW Daemon user guide - https://www.w3.org/History/19921103-hypertext/hypertext/WWW/...