Floor numbering in a building can cause misunderstandings between speakers of different varieties of the English language.

In most varieties, descending from English as spoken in the United Kingdom, the floor of a building which is entered at ground level from the outside is termed the ground floor, and the next floor up is the first floor. However in American English the floor at ground level is termed the first floor and the next floor up is the second floor.

See: Floor numbering, American and British English differences#Building layout