It's another use of "render" relative to the server such as converting non-HTML data inside database tables, json, etc --> rendered into HTML:

https://www.google.com/search?q=SSR+server+side+rendering

Many different perspectives of "rendering":

- SSR server-side rendering : server converting data to HTML

- CSR client-side rendering : e.g. client browser fetching and converting JSON/XML into dynamic HTML

- browser-engine rendering : converting HTML to operating system windowing GUI (i.e. "painting")