I used to confuse React server components with server-side rendering. One day I was watching the video on server components from Kodaps Academy, and heard a line that really made me think:

The interesting word in "server components" is "components", not "server".

What does it mean?

In server-side rendering (SSR), the full component tree is built on the server, with the resulting HTML sent to the client and hydrated. We have no control over which parts of the app are rendered on the server, and which are not.

With server components, only specific parts of the tree (specific components) are rendered on the server. We can choose what is rendered on the server and what on the client!

Pretty simple.

Of course, this is not the only difference. You can read more about server-side rendering vs server components on my blog.