Final answer:
The 'book of original entry' is known as a journal in accounting. It is where financial transactions are first recorded before being posted to the ledger as T-accounts. Other financial concepts include time deposit, transaction costs, and unit of account.
Step-by-step explanation:
The "book of original entry" referred to in the question is known as the journal in accounting. This is the first place where a company records financial transactions as they occur, in chronological order. Each entry in this book typically includes the date of the transaction, the accounts affected, the amounts to be debited or credited, and a brief description of the event. Then, these transactions are posted to the ledger, which is a collection of T-accounts. A T-account is a simplified representation of a ledger account and is depicted in a 'T' shape, clearly showing the two sides of each account; the left side for debits and the right side for credits.
Regarding other financial terms mentioned, a time deposit is an account such as a certificate of deposit where money is left in a bank for a set period to earn a higher interest rate. Transaction costs refer to the expenses incurred while securing a loan or finding a suitable lender or borrower. The unit of account is the standard numerical unit of measurement of the market value of goods, services, and other transactions within an economy.