What is money?

You ask: What is money?

Long ago, tribe trade rock for fish, fish for fur. Problem: what if fish-man not want rock? Trade break. So tribes pick one special thing everyone agree to want — shiny metal, later paper, now numbers in glowing box. That thing = money. Money not valuable itself. Paper just flat tree. Money work because whole tribe agree it work. It hold trade-power for later: Caveman sell mammoth today, buy berries next moon. If tribe stop believing, money turn back into flat tree. Cave wisdom: money is trust, hammered into thing you can hold.