参加 (cān jiā) is a verb meaning 'to take part in' or 'to join' an activity, event, or organization. It emphasizes active participation — not just attending, but engaging as a member or contributor. The character 参 means 'to participate' or 'to be involved', and 加 means 'to add' or 'to join'; together, they convey the idea of adding oneself to a group or activity. This word is commonly used for formal or structured events such as meetings, classes, competitions, ceremonies, and social organizations.

参加 is neutral in register and appropriate in both spoken and written Chinese. It typically takes a noun phrase as its object (e.g., 参加会议, 参加考试), and cannot be directly followed by a verb — you must say 参加 + [noun], not 参加 + [verb]. It’s often interchangeable with 加入 (jiā rù), though 加入 tends to emphasize becoming a lasting member (e.g., of a club or party), while 参加 focuses on involvement in a specific instance or event.