transaction
取引 — Phenomena
A dealing of buying and selling or of lending and borrowing.
Zhongtong Yuanbao Jiaochao noteYuan, Zhongtong era (from 1260)
Mameita-gin (with the 'gen' mark)AD 1695–1706
Free Imperial City of Frankfurt, One Thaler, 17721772
Money is needed in proportion to the number of transactions. As an economy grows, transactions increase, and money becomes scarce.