The word 星球 is formed through a direct conceptual combination of its two component characters: 星 (xīng), meaning "star" or "celestial body", and 球 (qiú), meaning "ball" or "sphere". It is a logical, almost pictorial fusion where the inherent spherical nature suggested by 球 is applied to the celestial object denoted by 星, thereby creating the composite idea of a "star-sphere" or "celestial sphere", which naturally extends to mean "planet" or "astronomical body". The formation is intuitive, building a new, concrete concept from two simple, concrete images.