BOOKS, commerce, accounts. Merchants, traders, and other persons, who are 
desirous of understanding their affairs, and of explaining them when 
necessary, keep, 1. a day book; 2. a journal; 3. a ledger; 4. a letter book; 
5. an invoice book; 6. a cash book; 7. a bill book; 8. a bank book; and 9. a 
cheek book. The reader is referred to these several articles. Commercial 
books are kept by single or by double entry.