Learning the design vocabulary is a bit challenging when starting out. How do we call that? Some folks have called them “islands”. I often think of it in terms of punching out from the background.
This technique is important in making stamps.
Another way of doing it without having to mess with converting text and doing a difference operation is to save the design as a PNG/bitmap. Then import it back in with the vector cut file.
Funny, here is a topic that asks your question and uses a similar example!