thanks for the confirmation jerez!
in england there is no diff between the two, right?
I have never heard of a Piso in England. We would call them apartments or flats I suppose.
I think the translation for Piso is Floor in the UK so perhaps it could be an apartment that covers a whole floor whereas you can have numerous apartments on a single floor? Complete guess.
However, direct translations often lose something in err, um … translation? 😕