"Lemme square up later" note

IOU

Think of what you might scribble on a napkin when borrowing cash, often starting with these three letters.

"Lemme square up later" is slang for settling a debt or paying someone back down the road. The word "note" hints at a written acknowledgment of that debt, which is exactly what an "IOU" is—a casual promise to repay. The phrase also plays on "square up" meaning to even things out, reinforcing the idea of an owed amount.