Online real estate listings
Properties listed for sale on the Internet.

Open house
A marketing tool in which a listing agent opens a house for view.

Open listing
A property given to a number of brokers to market at the same time.

Open space
Undeveloped land or common areas in a planned community reserved for parks, walking paths or other natural uses.

Option
A situation in which a buyer puts down money for the right to purchase a piece of real estate within a set time period but does not have an obligation to buy.

Oral agreement
Contractual arrangements that are not in writing and are usually not legally binding.

Original principal balance
The amount of principal owed on a loan before a borrower makes any payments.

Origination fee
A fee charged by most lenders--also called points--for processing a loan. A point is 1 percent of the total loan amount.

Overhang
A protruding structural feature.

Owner financing
A transaction in which the seller of a property agrees to finance all or part of the purchase.