Ohm 
A unit of electrical resistance. 

Ohmmeter 
A device used to measure electrical resistance. 

Ohm's Law
Formulas used to describe the relationship between current, voltage, and resistance. Current equals voltage divided by resistance. Used in determining the size for electrical components and wiring. 

Oil 
A greasy liquid used as a lubricant or a base for paint, or a finish for wood surfaces. Oils are derived from a variety of sources. 

Oil and Gas Lease 
An agreement that gives the right to explore for oil, gas, and sometimes other minerals and to extract them from the ground. Provisions include the granting of subsurface and surface rights, lease duration, extension terms, royalties, surface damages, assignments and warranties. 

Oil Finish 
A finish for wood where the oil is rubbed into the surface to preserve the wood. 

Oil of Cedarwood 
Oil derived from cedar used in cedar restoration.

OILSR 
Office of Interstate Land Sales Registration. Division of the U.S. Department of Housing and Urban Development that regulates offerings of land for sale across state lines. 

Oilstone 
A stone used to sharpen tools. The stone is lubricated with oil before use. 

Oil Well Cement 
Cement that cures at high temperatures used when drilling or repairing oil wells. 

Oleoresin Varnish 
Resins in a petroleum vehicle used to protect the finish on wood furniture and trim. 

Omnibus Clause 
Provision in a will that stipulates that any assets not enumerated still pass to the heirs. Alternately, a clause in liability insurance policies that extends coverage to unnamed others beyond the insured. 

On-Center
The distance between two items measured from the center of one item to the center of the other. Commonly used to describe distances between studs or joist in framing. 

One by 
Term meaning any lumber that is 1" thick - for example: 1" x 2"; 1" x 3"; 1" x 4". 

One-Hundred-Percent-Location 
The particular spot in an urban area where land value and rents are the highest; the BEST location. 

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. 

On-Site Management
Managing property directly at its location where it's functions may include showing prospective tenants the facilities, collecting rents, and doing upkeep on the property. 

Online Real Estate Listings 
Properties listed for sale on the Internet. 

Oolitic Limestone 
A type of limestone sometimes used in foundations.