429.603.  Definitions. — As used in sections 429.600 to 429.630, the following terms mean:

  (1)  "Commercial real estate", any real estate other than real estate containing one to four residential units or real estate classified as agricultural and horticultural property for assessment purposes as provided by section 137.016.  Commercial real estate shall include any unimproved real estate of any zoning classification, other than agricultural or horticultural real estate, being purchased for development or subdivision.  Commercial real estate does not include single-family residential units including condominiums, townhouses or homes in a subdivision when such real estate is sold, leased or otherwise conveyed on a unit-by-unit basis even though the units may be part of a larger building or parcel of real estate containing more than four residential units;

  (2)  "Owner", the owner of record of commercial real estate;

  (3)  "Real estate broker" and "real estate salesperson", as such terms are defined in section 339.010;

  (4)  "State-certified real estate appraiser", an appraiser as defined in section 339.503.