Promissory note
A promissory note is a negotiable instrument
Negotiable instrument
A negotiable instrument is a document guaranteeing the payment of a specific amount of money, either on demand, or at a set time. According to the Section 13 of the Negotiable Instruments Act, 1881 in India, a negotiable instrument means a promissory note, bill of exchange or cheque payable either...

, wherein one party (the maker or issuer) makes an unconditional promise in writing to pay a determinate sum of money
Money is any object or record that is generally accepted as payment for goods and services and repayment of debts in a given country or socio-economic context. The main functions of money are distinguished as: a medium of exchange; a unit of account; a store of value; and, occasionally in the past,...

 to the other (the payee), either at a fixed or determinable future time or on demand of the payee, under specific terms.

Referred to as a note payable in accounting, or commonly as just a "note", it is internationally regulated by the Convention providing a uniform law for bills of exchange and promissory notes.