This is the 2839th most frequent Russian word.
этажи
"Этажи" means "floors" or "stories" in a building.
In this sentence, 'этажах' is used to refer to the specific levels inside a building where people reside, emphasizing the still plural and spatial aspect of the term.
Они живут на верхних этажах этого здания.
They live on the upper floors of this building.
Here, 'этажи' represents the various levels encountered during the act of ascending a multi-story structure, showing its broader concept encompassing effort and progression.
Мы поднимались пешком через все этажи до самого верха.
We climbed on foot through all the floors to the very top.
In this case, 'этажах' conveys the idea of different horizontal divisions within a bookshelf, demonstrating its metaphorical adaptation to non-building contexts.