I've always been pretty sure that, like in Denmark, "the first floor" in some English-speaking areas means the floor *above* the ground floor.
Wikipedia shoots me down, it says it's the ground floor.
But the dictionary justifies the wonderful confusion:
the ground floor of a building.
the floor above the ground floor of a building.
Does somebody have any experience or rules as to where or when to use which?
Ken pointed to a wiki entry:
Floor numbering is the numbering scheme used for a building's floors. There are two major schemes in use across the world. In one system, used in the majority of Europe, the ground floor is the floor on the ground and often has no number or is assigned the number zero. Therefore the next floor up is assigned the number 1 and is the first floor. The other system, used primarily in the United States, counts the bottom floor as number 1 or first floor. The next floor up then becomes the second floor and so on.
Small wonder we get confused. Since there are no numbers in this apartment building, I think I'll continue to give directions with "one floor up", instead of "first floor".