Annual Fee
A flat, yearly charge similar to a membership fee.

Annual Percentage Rate (APR)
A measure of the cost of credit that expresses the finance charge, which includes interest and may also include other charges, as a yearly rate.

Finance Charge
The dollar amount you pay to use credit. Besides interest costs, it may include other charges associated with transactions such as cash advance fees.

Grace Period
A time, about 25 days, during which you can pay your credit card bill without paying a finance charge. Under almost all credit card plans, the grace period only applies if you pay your balance in full each month. It does not apply if you carry a balance forward. Also, the grace period does not apply to cash advances.

Interest Rate
Interest raes on credit card plans change over time. Some are explicitly tied to changes in other interest rates such as the prime rate or the Treasury Bill rate and are called variable rate plans. Others are not explicitly tied to changes in other interest rates and are called fixed rate plans.