Any industry, process of manufacture, fabrication, assembly, disassembly, conversion or alteration. For the purpose of this section, any business use shall be deemed to be an industry where it employs more than five persons in the processing or manufacturing of a product or uses more than a total of 25 horsepower manufacturing operations, but is not intended that a retail store or service establishment such as a hotel, department store or bank be limited in the number of its employees or in the horsepower used for heating, air conditioning and other similar nonprocessing or manufacturing operations.