1. Refers to The Building Owners and Manager’s Association. An International Organization made up of Building Owners, Building Managers and suppliers of the same. Because of its size and influence the organization establishes a variety of recommended guidelines, such as the B.O.M.A. method of measurement.
2. Method of Measurement. Is generally accepted throughout the office building industry as the standard and fair method of measuring office space. Some landlords use other methods, including their own. To determine the Usable area of your space, you must measure from the inside finished surface of the corridor wall and the dominant portion of other perminant walls (dominant portion of exterior walls, i.e. could be glass) to the center of the wall that separates your office from the adjoining office. Columns and interior walls should not be deducted from the measurement. To determine the Rentable area of your space, you must first determine the rentable area of your floor. This would be accomplished by measuring the inside finished surfaces of the outer building (might be outer glass to outer glass that makes up the exterior walls of the floor). Remember it’s length times width equals square footage. When measuring, exclude any "vertical penetrations" such as stairwells elevator shafts, flues, vertical ducting etc. before you determine the Usable area of that floor. This would be accomplished by taking the rentable measurement and subtracting areas of common use to the tenant, i.e. corridors, restrooms, utility closets, janitorial closets and building ammenities located on that floor, such as a common conference room. To determine your rentable area, usable area and common area factors apply the following conversion formulas:
   Rentable area divided by Usable area = Rentable/Usable Ratio.
   Usable area times Rentable/Usable Ratio = Rentable Area.
   Rentable Area divided by Rentable/Usable Ratio = Usable Area

This definition is in context to Commercial Real Estate. See more contextual defintions for B.O.M.A.