A dynamic website takes a bunch of data on the backend – content, databases, layout etc. and sends the user a finished product when they request it.
A static website generator has a set of HTML files delivered immediately to the user when they arrive to the site. These files are the finished product, holding all the latest data, layout etc. These files are delivered together when the user reaches the site. Content is often written in Markdown or another format that can be transformed into the final HTML for display in the browser.
Static websites can't really offer a real-time experience or much in the way of user involvement.