If trade and labor are supposed to be charity, money given in exchange is a token of thanks. Monetary exchange is, in essence, a declaration that someone did good toward oneself. In a real sense, it makes the "what" money is into information, yet it requires anchor in reality.
A proposed definition: token of thanks, abstracted trade, and evidence of goodwill
Another popular definition: medium of exchange, unit of account, and store of value
I would love to hear your thoughts!