· 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.