账单
zhàng dān · HSK 7
bill
🧾 账单 = 账 account + 单 single sheet → the account-sheet you pay
账 carries the 贝 (shell/money) radical, marking it as money-account; 单 means a single slip or list. Together: the itemized money-slip, a bill. Sound: zhàng dān.
账 — shell radical 贝 + length 长
账 is a semantic-phonetic compound. The shell radical 贝 (originally cowrie shells used as money) signals a connection to wealth or financial matters, while 长 (zhǎng/cháng) provides the sound. It means 'account' or 'debt,' and is a later variant of the older form 帳.
单 — 叩 (two mouths 口) over 甲 (shield/armor)
Originally a pictograph of a forked hunting weapon or shield with two prongs at the top. The ancient form shows a Y-shaped tool, later stylized into the modern shape. The meaning shifted from the weapon to 'single' or 'one,' possibly because it was a single-handed tool.