‘卫星’ literally means ‘guardian star’—‘卫’ (wèi) means ‘to guard, protect, or defend’, and ‘星’ (xīng) means ‘star’. Historically, the term evoked celestial bodies that orbit and accompany larger ones, like moons circling planets. In modern usage, it almost exclusively refers to artificial satellites—human-made objects launched into orbit around Earth or other celestial bodies for communication, weather monitoring, navigation (e.g., GPS), scientific research, or military purposes.

Unlike natural satellites (e.g., the Moon, called 月球 yuèqiú in Chinese), 卫星 is a neutral, technical term used across formal and everyday contexts. It appears frequently in news reports, science education, and daily life—such as when discussing satellite TV, satellite images, or China’s BeiDou Navigation Satellite System. The word carries no emotional connotation and is always countable: you say 一颗卫星 (yī kē wèixīng, ‘one satellite’) or 多颗卫星 (duō kē wèixīng, ‘multiple satellites’).