EBIAT
Stands for Earnings Before Interest After Tax.
Another way to think about it is that EBIAT = Net Income + Interest. In other words, you’re un-levering the business. The reason you do this, is once we get down to Free Cash Flow, you want that to be representative of the entire business, not just the business after interest payments have been made.
In the room
EBIAT is the bridge into unlevered free cash flow, and that's the only reason it comes up. If you're asked why a DCF starts from EBIAT instead of net income, the answer is that you're valuing the whole business, not just the equity — so you strip out the effect of how it happens to be financed.