coin koin/ noun​​

a flat, typically round piece of metal with an official stamp, used as money.

Coins were introduced as a method of payment around the 6th or 5th century BCE. The invention of coins is still shrouded in mystery: According to Herdotous (I, 94), coins were first minted by the Lydians, while Aristotle claims that the first coins were minted by Demodike of Kyrme, the wife of King Midas of Phrygia. Numismatists consider that the first coins were minted on the Greek island of Aegina, either by the local rulers or by king Pheidon of Argos.