Index
A statistic that indicates some current economic or financial condition. Indexes are often used to make adjustments in wage rates, rental rates, loan interest rates, and pension benefits set by long-term contracts. To adjust contract terms according to an index.

Insurance (Mortgage)
A service, generally purchased by a borrower, that will indemnify the lender in case of foreclosure of the loan. Indemnification is generally limited to losses suffered by the lender in the foreclosure process.

Interest
Cost of the use of money. The type and extent of ownership.

Interest Rate
The percentage of a sum of money charged for its use. The rate of return on an investment.