Floating Lien
A drunk trying to walk home from the bar, stopping every 20 feet or so to rest. Floating lean...wait, that's a different kind of lean.
Here, we're talking lien, like a claim against property in order to repay a debt. If you owe a big tax bill, for instance, the government might put a lien on your house. Then, if you sell the house, they have dibs on whatever part of the sale price pays the taxes.
It's also a term used in conjunction with the idea of collateral. You get a loan by putting your mom's diamond pendant up as collateral. The bank now has a lien on that jewelry.
In the case of a floating lien, no specific piece of property gets identified. Instead, the lien covers a collection of property. A company can secure a loan using a vague hodge-podge of property as the collateral...and the property included in that group can change over time.