Impound account or escrow account
An account specifically set up by a lender to hold funds that are set aside for the payment of property taxes and insurance. These funds are held in escrow until disbursed on behalf of the borrower to the appropriate parties.

Index
When used in a note or credit agreement, the measurement used to decide how much the annual percentage rate will change at the beginning of each adjustment period. Generally, the index plus margin equals the new rate that will be charged, subject to any caps. Different lenders use different index rates (cost of funds index, prime rate and so forth).

Inflation rate
The increase in price of consumer goods, usually expressed as a percentage over a specific period of time.

Initial rate
The starting interest rate. Some people call this a teaser rate, because it gives you low interest and low monthly payments at the beginning, but may adjust up at the next adjustment period (it will usually adjust even if the index doesn't go up, since it's lower than index plus margin for the initial period).

Interest
A charge paid for borrowing money.

Interest-only payments
Some lenders permit you to pay only the interest due on a loan for a portion of the loan term, which lowers your periodic payment, but does not decrease your principal balance on the loan. See balloon loan and balloon payment.

Interest rate
Cost for the use of a loan, usually expressed as a percentage of the loan, paid over a specific period of time. The interest rate does not include fees charged for the loan. See annual percentage rate.

Interest rate cap
A limit on how much the variable interest rate can increase at any one time. Many real estate loans have both annual (or semi-annual) caps and lifetime caps, which limit the amount your payments can increase in an adjustment period and over the life of the loan.

Investment property
Property that is purchased to generate rental income, or to be sold once it's appreciated in value.