The difference in terminology between England and America regarding the naming of the first floor of a house (i.e., ground floor in England and first floor in America) is rooted in historical architectural conventions and regional linguistic differences.
England: In England and many other parts of the world, the ground floor is called the "ground floor" because it is at ground level, directly on the ground, and typically where you enter the building. This naming convention is straightforward and reflects the physical layout of the building.
America: In the United States, the naming of floors is influenced by architectural traditions and linguistic variations. Historically, American architecture has been influenced by both British and European styles, but some differences emerged over time. The American convention of calling the first floor the "first floor" is believed to have been influenced by the French language.
In French and some other Romance languages, the term "premier étage" (first floor) is used for the level above the ground floor, while "rez-de-chaussée" (ground floor) is used for the level at ground level. When French-speaking settlers came to America, their architectural influence brought with it the use of "first floor" for the level above the ground floor.
While some buildings in America do use the term "ground floor," it is more common to refer to the level above the ground floor as the "first floor."
It's important to note that language and architectural conventions can vary between different regions and countries, so there might be exceptions to these general naming conventions in both England and America. Additionally, architectural practices and naming conventions may continue to evolve over time.