What Benoit said is right. I would just add that if you play (3rd, 5th, 1st) or (3rd, 1st, 5th), both will be called "first inversion". Same thing for the root position or the second inversion.
Jean-François Renaud
http://www.myspace.com/jeanfrancoisrenaudmusic
http://www.myspace.com/jeanfrancoisrenaudmusic