When to use it
Use it the first time an unfamiliar acronym or term comes up in a meeting. Asking early is quick and usually helps someone else in the room too. Waiting means you might act on a wrong guess, which is much harder to fix later.
Example
Lead: “So the ARR impact is what we're watching.”
You: “Before we go on, what does ARR stand for here?”
Lead: “Annual recurring revenue.”
In an email or Slack message
If you'd rather not interrupt, ask in the meeting chat: “Quick one: what does ARR stand for here?” Or keep a running list and ask a teammate afterward.