Zach Leatherman breaks down what SSR means in various contexts (component frameworks, app frameworks. Here’s the gist, but the details are good to so def read Zach’s full post:
Application frameworks most often define SSR as the alternative to SSG (static site generation). A runtime server is used to render the components on request.
Component frameworks define SSR as generating static HTML from a component definition. They offer no preference as to whether this should or can happen at build time or at request-time.