The term "主營業(yè)務(wù)" in English is referred to as "Main Business" or "Core Business". This term is used to describe the primary activities or operations that a company is engaged in. It is the source of most of the company's revenue and profits. The main business is what the company is known for and what makes it unique in the marketplace.

For instance, the main business of Apple Inc. is the design, manufacture, and marketing of mobile communication and media devices, personal computers, and portable digital music players. The company also sells a variety of related software, services, accessories, networking solutions, and third-party digital content and applications.

The main business is crucial for a company's survival and growth. It is the area where the company has the most expertise and competitive advantage. It is also the area where the company invests the most resources and attention.

The main business is not static. It can evolve over time as the company grows, the market changes, or the company diversifies its operations. For example, Amazon started as an online bookstore, but its main business has evolved to include e-commerce, cloud computing, digital streaming, and artificial intelligence.

Understanding a company's main business is important for investors, customers, employees, and other stakeholders. It helps them understand the company's business model, competitive position, and growth prospects. It also helps them make informed decisions about investing in the company, buying its products or services, working for the company, or doing business with the company.

Expansion Knowledge: The concept of "core business" is closely related to the concept of "core competency". Core competency is a unique capability or skill that a company has and that gives it a competitive advantage. It is what the company does best and what differentiates it from competitors. A company's main business is usually built around its core competencies. For example, Apple's core competencies in design and innovation are reflected in its main business of making innovative and well-designed devices.