Waterfall
the order in which money is handed out floor by floor: senior → mezz → equity; it works both in regular payments and in a collapse
In more detail
The queue for money in a liquidation: first senior debt, then junior debt, then the owners' share. Losses go from the bottom up, returns from the top down.
It was invented so that money of different degrees of boldness could take part in one deal, knowing its place in advance.
Where it appears in the course
In the academy “Waterfall” is not a definition but an operation: you post it yourself and watch what it does to the balance sheet.