账册 (zhàngcè) is a formal noun meaning 'ledger'—a book or digital record used to track financial transactions, such as income, expenses, debts, and payments. The first character 账 (zhàng) means 'account' or 'financial record', while 册 (cè) means 'book' or 'register', literally 'a bound volume of pages'. Together, they denote a systematic, often official or business-oriented, record-keeping book.

This word is commonly used in accounting, auditing, small business management, and government finance contexts. It implies accuracy, continuity, and accountability—unlike casual notes or personal diaries. While modern ledgers are often digital, 账册 still refers to any authoritative, organized financial record, whether physical or electronic. It carries a slightly formal or traditional tone and appears frequently in legal documents, tax filings, and internal company reports.