楼层 (lóu céng) literally combines 楼 (lóu), meaning 'building' or 'multi-story structure', and 层 (céng), meaning 'layer' or 'level'. Together, they refer specifically to a horizontal level or story within a building — for example, the 'third floor' or 'ground floor'. Unlike the English word 'floor', which can also mean the surface you walk on, 楼层 always refers to the structural level as part of a building’s vertical organization.

This term is used in everyday contexts such as giving directions ('Go to the fifth floor'), describing property features ('This apartment has three floors'), or reading signs in elevators and lobbies. It is neutral in register and appropriate in both spoken and written Chinese. Note that 楼层 is a countable noun and typically appears with numerals or measure words like '第' (e.g., 第二楼层 or more commonly 第二层) or classifiers like '个' in informal speech.