阴 (Shadow) refers to the dark shape produced when an object blocks light. It is a natural phenomenon that occurs in various environments, such as outdoors under sunlight or indoors with artificial lighting. Shadows can change in size and shape depending on the light source's angle and intensity. In traditional Chinese philosophy, 阴 is associated with the concept of 阴阳, representing the passive, dark, and feminine aspects of existence. It contrasts with 阳, which symbolizes brightness, activity, and masculinity. Together, these concepts illustrate the balance and interdependence of opposing forces in the universe.