A piece of paper money issued by a bank or government that represents a specific amount of currency.
From 'bank' and 'note'—originally, banks literally issued written notes promising to pay the bearer a certain amount of precious metal, which evolved into the paper money we use today (16th-17th century).
Banknotes only work because everyone agrees they're valuable—they're essentially trust made into paper, and if people stopped believing in that trust, the paper would be worthless!
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