Floors of a Commercial Building
There are some important differences between British English (BrE) and American English (AmE) in talking about the floors in a commercial building.
In BrE the floor at the level of the surrounding land or ground is called the ground floor (this is the floor where you usually enter a building). In AmE the same floor is called the first floor. The floors above are numbered starting from the ground or first floor, so there is usually a difference of one level in BrE and AmE usage:
- BrE: ground floor, 1st floor, 2nd floor, 3rd floor etc
- AmE: 1st floor, 2nd floor, 3rd floor, 4th floor etc
Many commercial buildings also have a "mezzanine" floor, which is a kind of "half-floor". This diagram shows a six-storey building that has a mezzanine and two basement levels below.