You have summarized my first two months at a new job.

I joined as a lead and spend a good deal of time in meetings where they discuss new features and tasks. Before the meeting, I open the company's acronym cheatsheet just to be able to keep up. Then after a long monologue from a manager that ends with "Any questions," I'm the guy who asks: "What's <product-name>?"

It sucks because I appear incompetent. But it has also helped us onboard people better. One of the first tasks I assigned to my team was to update the README.md files of all code bases they touch. It might seem obvious to the old timers what everything does, they have spend years working on it. But to the avalanche of new developers they are hiring, a code base that has code and no description is a source of confusion.