n[C]
[Date: 1300-1400; Origin: story; perhaps because some medieval buildings had paintings on their walls telling stories]
a floor or level of a building
　a staircase leads to the upper storey
two-storey/five-storey etc
(=having two etc storeys)

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WORD CHOICE: storey, story, floor
Storey (BrE) or story (AmE) is usually used to talk about the structure of a building : a building dozens of storeys high | a three-storey house
The plural of story is stories : The office block was 20 stories high.
To talk about where someone or something is in a building, use floor : We went up to the top floor. | He works on the fifteenth floor. | Is there a bathroom on this floor?

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