交易
jiāoyì · HSK 3
deal
🤝 交 = exchange/hand-over + 易 = change/easy; together: hand-over-and-change = trade
交 carries the sense of crossing or handing across (same character as in 交换 exchange). 易 means change (also in 容易 easy, from the idea of an easy swap). A 交易 is literally a hand-over-and-swap: a transaction.
交 — top 亠 + 父-like crossed legs
Originally a pictograph of a person standing with legs crossed, showing the idea of crossing or intersecting. From this concrete image, the meaning extended to abstract senses like 'exchange,' 'interact,' and 'hand over.' Modern uses such as 交流 (exchange) and 交通 (traffic) all trace back to this core notion of crossing.