The word 楼下 is formed by directly combining two meaningful characters: 楼 (lóu), which means "building" or "upstairs", and 下 (xià), which means "down" or "below". The second character 下 is placed after 楼 to specify a spatial relationship, creating a concept that literally translates to "the down/downstairs part of the building", effectively meaning "downstairs" or the area beneath or at the foot of the building.