What do we call money used for buying and selling?

The story behind the answer

In the Middle Ages, everyday buying and selling was done with stamped metal money. Kings, emperors, and city-states ran mints that guaranteed weight and purity, so value came largely from the silver or gold content. That’s why “banknotes” and “paper money” don’t fit this era in Europe; true paper money emerged in Song-dynasty China and only much later in the West, while “currency” is the general term rather than the specific medium people carried.

Control of minting was a key source of power and revenue. Rulers sometimes “debased” issues by lowering silver content, and people clipped edges for slivers of metal—both major medieval problems. Common types included the silver penny/denier/pfennig, while high-value trade ran on gold pieces like the Florentine florin and Venetian ducat, accepted across borders.