A promise to pay a specified amount on demand or at a certain time WordNet 3.0 & Open English WordNet

A promissory note, sometimes referred to as a note payable, is a legal instrument, in which one party promises in writing to pay a determinate sum of money to the other, either at a fixed or determinable future time or on demand of the payee, under specific terms and conditions. Wikipedia

A contract binding one party to pay money to a second party Wikipedia Disambiguation

Negotiable instrument, wherein one party makes an unconditional promise in writing to pay a determinate sum of money to the other Wikidata

A commercial document issued by a seller to the buyer, indicating products or services already provided to the buyer as well as the corresponding price that the buyer has to pay. OmegaWiki

A written or printed paper acknowledging a debt, and promising payment. Wiktionary

Written or printed paper acknowledging a debt, and promising payment. Wiktionary (translation)

A written guarantee to pay or repay a given sum; a receipt; a promissory note. Wiktionary

A document saying that someone owes a specific amount of money to someone else, often with the deadline and interest fees; the primary purposes of a promissory note are to evidence the debt obligation incurred, and to establish terms for payment thereof. Wiktionary

Document saying that someone owes a specific amount of money. Wiktionary (translation)