Storey

A storey (British English), story (American English) or floor level is any level part of a building with a floor that could be used by people for work, play, a place to live, etc. The word is known as "storeys" in the United Kingdom and "stories" in the United States.
Both British and American English have different floor numbering systems. In British English, the level above the ground floor is the "first floor", whereas in American English, it is the " second floor". 
Basements may be considered storeys, especially if they're partly above ground, as in a walkout basement. In which cases, it's typically called the "lower floor", " lower ground floor ", " terrace level ", etc. In some buildings, the top storey is a finished attic or garret.
Storeys can be used to classify buildings as low-rise, mid-rise or high-rise.
Low-rise buildings have one to four storeys.
A mid-rise building is typically 5-9 storeys.
And a high-rise building is typically 10 or more storeys.