Can someone please ELI5 on the meaning of these things? Googling around just sends me down a scholarly rabbit hole of more words I don't understand.

I did that once to a paper that I don't understand. That is, I read and look up stuff until I think I understood things.

I learned a lot by doing that. But it took a lot of work, and I forgotten most of it if it wasn't added to anki. Good thing that I wrote it down in my notes.