An industry is a group of companies with the same focus. Some examples of common industries are automobile production, tobacco, farm goods and office supplies.
Industries that have a common goal fall under different sectors. For example, the utilities sector includes industries like electricity, water and gas. Industries are not monolithic entities, and they encompass a large number of different companies that all produce the same product or service. Industry is also the term for the manufacture of goods using machinery in factories. Industry and industries typically go hand in hand, as industries use machinery and factories in order to produce the goods they sell.