IOU is an acronym for 'I Owe You' and is a term used to refer to a DEBT or promise of payment. A MARKER is a written document that serves as evidence of a DEBT, such as a promissory NOTE. A NOTE is a written document that serves as evidence of a DEBT, such as a promissory NOTE or bill of exchange. A CHIT is a short written document that serves as evidence of a DEBT, such as a promissory NOTE or bill of exchange. A DEBT is an amount of money owed by one person to another. Vowels of Poverty is a phrase used to describe the letters I, O, U, which are often associated with DEBT and poverty.