OBLIGEE:
The lender in a loan transaction -- the person to whom, as a result of her actions, another person owes an obligation. See also "mortgagee" or "chargee".

OBLIGOR:
The borrower in a loan transaction -- the person who owes an obligation to another.

OBSOLESCENCE:
The loss of value or usefulness resulting from advances in technology and the passage of time.

OCCUPANCY:
The physical control and possession of a building or property.

OCCUPANCY PERMIT:
Issued by local building departments, permission to enter and occupy a newly built or renovated dwelling after an inspection has established that there are not potential threats to the safety of occupants.

OCCUPANCY RATE:
The percentage of available rental space that is actually rented and in use in a given building or community.

OFFER:
To make available, to express a willingness (whether in writing or orally), in the case of real estate, to inform another party of your willingness to sell or buy a specific property on terms set out in your offer. An offer, once made, may be accepted at any time before it is rescinded. Once accepted, the offer and acceptance generally form a binding contract.

OFFER AND ACCEPTANCE:
Components of a contract, applicable to the real estate situation where a Purchaser may make an offer on a property and the Vendor may accept that offer.

OFFER TO PURCHASE:
A written expression of a person's willingness to purchase a certain property on terms expressed in the offer.

OFFER TO SELL:
In general, a written expression of a person's willingness to sell a certain property on terms expressed in the offer.

OFFEREE:
The person who receives an offer.

OFFEROR:
The person who makes an offer.

OFFICE OF INTERSTATE LAND SALES REGISTRATION:
A HUD agency which has the responsibility for enforcing the Interstate Land Sales Full Disclosure Act.

OFFICE PARK:
Similar to an industrial park but for offices, a property designed and developed specifically to attract corporate offices and provide them with all facilities required to carry on business.

OFFICIAL MAP:
The pictorial depiction of the land-use control areas of a municipality used by the local government.

OFF-SITE COSTS:
Expenditures for facilities required by a particular development but located elsewhere (such as streets, schools, sewers and waste disposal facilities).

OFF-SITE IMPROVEMENTS:
Facilities which are required for the use and development of a particular property but which are located elsewhere.

OFF-STREET PARKING:
Spaces for cars which are located on private property rather than on public streets. Local by-laws may require that any new commercial, residential or retail development provide a certain number of parking spaces as part of the development.

OIL AND GAS LEASE:
An agreement in which a property owner allows another person to exploit any oil or gas deposits on the land for a certain period of time in exchange for periodic payments.

ON OR ABOUT:
Legalese way of noting that the exact date of an event has not been determined.

ON-SITE IMPROVEMENTS:
Work completed on a property which adds to its value or utility.

OPEN AND NOTORIOUS:
See "notorious".

OPEN END MORTGAGE:
A loan which is specifically drafted to allow the borrower to borrow further funds at a later date without requiring the preparation and registration of new mortgage documentation.

OPEN HOUSE:
An advertised period of time in which a property which is for sale is available for inspection by prospective purchasers.

OPEN LISTING:
An agreement whereby the owner of the property may enlist more than one broker to attempt to sell the property and the commission is payable only to the successful agent.

OPEN MORTGAGE:
A mortgage which may be prepaid in full or in part at any time during that life of the mortgage without notice, bonus or penalty.

OPEN SPACE:
Empty or vacant land, often parkland which is considered an amenity for surrounding residences.

OPERATING EXPENSES:
Periodic expenses payable on an income-producing property that are directly attributable to the use of the property for the purpose of producing income.

OPERATION OF LAW:
The effect of a given statute or rule upon a situation. For example, a joint tenant becomes the sole owner of a property by operation of law upon the death of the other joint tenant.

OPTION RISK:
The downside of giving a borrower an option, such as the possibility that she may prepay an open mortgage and reduce the income generated to the lender by the accumulation of interest over the life of the mortgage.

OPTION TO PURCHASE LEASED PROPERTY:
A clause of a rental agreement allowing the tenant the right to buy the leased property upon terms and conditions set out in the agreement.

ORAL CONTRACT:
A legally binding agreement crated by spoken words rather than reduced to writing. In many jurisdictions, oral contracts with regard to land are unenforceable in any circumstance.

ORDINANCE:
A rule or by-law enacted by a local government.

ORIGINAL EQUITY:
The owner's original downpayment on a property.

ORIGINAL FACE VALUE:
The principal amount owed on a mortgage on the date of its negotiation as shown on the "face" of the agreement.

ORIGINAL PRINCIPAL BALANCE:
See "original face value".

ORIGINATION FEE:
See "commitment fee".

OSTENSIBLE AUTHORITY:
The suggestion that one person has the right to act on behalf of another person created by the actions of the "agent" and the inactivity or lack of protest of the "principal".

OUTBUILDING:
A structure that is not a part of the main building but is necessary to the full enjoyment of the property (i.e. a shed, garage, etc.).

OUTSTANDING BALANCE:
The amount of money (including principal and interest) owing at a given date on a loan or mortgage.

OWNER FINANCING:
See " mortgage back" or "vendor take-back mortgage".

OWNER OCCUPIED:
Any property where the owner resides in all or part of the property.

OWNER'S TITLE INSURANCE:
A title insurance policy which covers the owner of the property from title defects and other flaws which were not apparent at the time of the purchase.