主角 literally means 'main role' or 'principal part': 主 (zhǔ) means 'main', 'primary', or 'host', and 角 (jiǎo) means 'role' or 'character'—originally from the theatrical term for a performer’s part. Together, they refer to the central figure in a story, film, play, or narrative—the character whose goals, struggles, and development drive the plot forward.

While often used in literary and cinematic contexts, 主角 is also widely applied metaphorically in everyday speech—for example, to describe someone who takes center stage in an event, conversation, or even a family photo. It carries a neutral-to-positive connotation, emphasizing importance and prominence rather than moral judgment. Unlike English 'protagonist', which can sound formal or academic, 主角 is common in both spoken and written Chinese, including social media, news reports, and casual storytelling.