A villa is more like a house (here you can get a stand alone villa or a villa in a compound which is like its own community within walls, usually has facilities like pool and gym and has 24 hr security), an apartment is more of a smaller dwelling usually in a tall building and a flat is usually a small dwelling in a block of flats if you know what I mean....(as opposed to a tall building?)

That is what they are in Australia anyway ! I have only been here two weeks so someone correct me if it's different here... lots of things are different here ;)