Definition: Promissory note
External debt - IMF
An unconditional promise to pay a certain sum on demand on a specified due date. Promissory notes are widely used in international trade as a secure means of payment. They are drawn up (issued) by an importer in favor of the exporter. When the latter endorses the note, provided the importer is creditworthy, a promissory note is traded.
International Monetary Fund (IMF), "External Debt Statistics: Guide for Compilers and Users; Appendix I. Specific Financial Instruments and Transactions: Classifications", Washington D.C., 2003