The term "core business" refers to the primary activities or operations that are central to a company's reason for existence. It is the main activity or line of business in which an organization specializes and generates its revenue from, as it directly relates to their overall mission and goals. The core business can also be thought of as the foundation upon which a company builds its success, and it typically involves activities that are critical to the company's long-term survival and growth. In other words, the core business is what an organization does best, and it forms the basis for their competitive advantage in the marketplace.