貝
かい · kai · JLPT N3 · noun
shell
🐚 Cowrie shell glyph; shells were money, so 貝 sits in 買 buy and 財 wealth
貝 began as a drawing of a cowrie shell. Ancient China used cowries as currency, so this part marks money words: 買 buy, 財 wealth, 貨 goods, 費 cost. Sound hook: kai, a shell washed up on the kaigan (海岸, seashore).