InterestThe cost of using money.
Interest RateInterest paid divided by the principal amount borrowed.
AmortizationDebt payment which includes repayment of both principal and interest. Over time, a declining portion of the payments is interest.
A deduction from income tax owed based on certain types of interest paid such as for a mortgage payment or margin account.
Simple InterestAn interest calculation based only on an original principal amount.
Compound InterestAn interest calculation based on original principal plus accumulated interest already paid.
Cheap MoneyWhen interest rates are low, the cost of borrowing is reduced.UsuryIllegal practice of charging an excessively high interest rate on loans.