出席 (chū xí) is a formal verb meaning 'to attend'—especially at official, academic, or professional events such as meetings, conferences, ceremonies, or lectures. Literally, 出 (chū) means 'to go out' or 'to appear', and 席 (xí) originally referred to a mat or seat used for sitting in ancient China; together, they evoke the idea of 'appearing at one’s designated seat'—a vivid image of showing up appropriately at a scheduled gathering. This word carries a tone of responsibility and formality, implying presence is expected or required.

It is commonly used in written reports, official notices, and polite speech. Unlike more casual alternatives like 参加 (cān jiā), 出席 suggests higher status, obligation, or visibility—for example, a company executive attending a shareholder meeting or a diplomat at an international summit. It is rarely used for informal gatherings like birthday parties or casual get-togethers, where it would sound overly stiff or ironic.