Nomisma

Nomisma (Greek: νόμισμα) was the ancient Greek word for "money" and is derived from nomos (νόμος) meaning "'anything assigned,' 'a usage,' 'custom,' 'law,' 'ordinance,' or 'that which is a habitual practice.'"

...but money has become by convention a sort of representative of demand; and this is why it has the name 'money' (nomisma) – because it exists not by nature but by law (nomos) and it is in our power to change it and make it useless.

— Aristotle, Nicomachean Ethics [1133b 1].

The term nomos may also refer to an approximately 8 gram Achaean coin denomination.