Obligatory
The legal requirement of a debtor, obligor, to pay a debt and the legal right of a creditor, obligee, to demand satisfaction of a debt or enforce payment in the event of default.

Obligee
The person to whom a debt or obligation is owed.

Obstruction
Blockage. A clog. Something that prevents passage or operation.

Occupancy
Residing in or using real estate.

Offer
An expression of willingness to purchase a property at a specified price; presenting for acceptance a price for a property parcel; the bid price in a real estate or security transaction.

Offer and Acceptance
These two requirements of a contract forming mutual consent combined with valuable consideration are the major elements of a contract.

Offer To Purchase
A proposal to buy property at a specified price whereupon the seller has the options of accepting or rejecting the offer or making a counteroffer.

Offeree
One who receives an offer.

Offerer
One who extends an offer to another.

Office Condominium
The units are used as commercial offices.

On-Site Improvements
Directly enhancing the physical nature of the property such as renovating a building, installing a new driveway and parking lot and gardening.