The word "上楼" is formed by conceptually combining two fundamental ideas: the directional movement "上" (shàng), meaning "to go up" or "upward", with the object or location "楼" (lóu), meaning "building", "floor", or "story". It is constructed by placing the directional action first, which then logically acts upon or relates to the subsequent spatial object, creating a unified mental image of the action of ascending within the context of a multi-level structure. This direct semantic pairing results in a compound whose meaning emerges intuitively from the sequence, moving upward to or within a building.