A storey is any level part of a building with a floor that could be used by people for living work storage recreation cetera. Plurals for the word are storeys and stories
The terms floor level or deck are used in a similar way except that it is usual to talk of a 7 – storey building, but the 7th floor. The floor at ground or street level is called the ground floor it has no number and the floor above it is called first in many places. In other places ground floor and first floor are synonymous. The words storey and floor exclude levels of the building that are not covered by a roof such as the terrace on the top roof of many buildings.