'乘务员' (chéng wù yuán) literally combines '乘' (to ride or board), '务' (duty or service), and '员' (person or staff member), meaning a person who performs service duties on a vehicle. It most commonly refers to flight attendants on airplanes or conductors/attendants on trains and long-distance buses — professionals responsible for passenger safety, comfort, and onboard service.

This term is formal and neutral in register, used in official announcements, travel contexts, and everyday speech when referring to transportation staff. Unlike more generic terms like '服务员' (server), '乘务员' specifically denotes service personnel operating within moving vehicles, emphasizing mobility and transit-related responsibilities. It does not apply to static service roles such as hotel staff or restaurant servers.