Okay kiddo, do you know what an announcement is? It's when someone tells a bunch of people about something important or exciting.
Well, a Broad Agency Announcement (BAA) is an announcement that the government makes when it wants to get ideas or proposals from people or companies for new projects or research.
It's called "broad" because it's open to anyone who has a good idea or proposal, not just specific groups or companies.
So, let's say the government wants to find a new way to clean up pollution. They might put out a BAA asking for ideas from anyone who thinks they have a good solution.
Then, people or companies who are interested can send in their ideas or proposals. The government will review them and choose the best ones to fund and work on.
And that's what a Broad Agency Announcement is!