A planet to me, is a fairly round object that orbits the sun directly (not orbiting another planet which is orbiting a star, unless its a double planet), and a certain size, I would include Pluto and 2003 HB313? As it said in the programme last night if the new definition of a planet excludes Pluto some may well ignore the revised definition. Maybe we should have the Inner Planets, the Gas Giants and the Keiper Belt Planets