Payment for the use of someone else’s money. What you do not get in bankruptcy if you are undersecured. What you get to accrue but not necessarily receive current payment of if you are oversecured. But see Single Asset Real Estate.
Something (a lien, ownership interest, tenancy or other unspecified “interest”) that property can be sold free and clear of under Section 363(f). This interest will attach to the sale “proceeds” of which there may or may not be enough to fully compensate the holder of the interest for its loss.