space, house

宇 is composed of 宀 (roof) and 于 (go). 宀 is a pictograph of a roof, while 于 depicts a stream of breath rising and bending due to obstruction, and means a boundary or limit. Therefore, 宇 conveys the idea of the boundary of a roof, and its original meaning is the eaves. The eaves cover the living area of a house, so 宇 also came to mean a house, and later broadly referred to space.