SubscribeWhile few Americans not permanently addled by overexposure to PBS routinely refer to their apartments as "flats," it has been standard usage in Britain since the 19th century. One might logically assume that, because most "flats" occupy a single story of a building, the word simply comes from the "flatness" of the abode, and one would be largely correct. But "flat" in this sense is actually derived from the obsolete Scots word "flet," meaning "floor" or "interior of a house" back in the 15th century. Then again, that "flet" was derived from the same Germanic root as our modern adjective "flat," so you can probably safely ignore that little Scottish detour.
Also, I belive that a flat is defined as being, well, flat - that is, it's on a single floor. For example, I would not call a duplex apartment a flat.
posted by kickingtheground at 12:16 AM on March 1, 2005