20. The goal of terms in science is to aid our understanding of the universe, not hinder it. For this reason, definitions, particular baseline definitions, need to be simple. I'm not an ornithologist but I have a pretty good idea of what a "bird" is and any 5 year old does as well. Yet I guarantee most if not all ornithologists cannot name all 10,000+ species of birds. In a similar vein, why does it matter if kids can't name all the planets?
Agreed that the IAU is so far off the mark it's not funny considering they are supposed to be a major scientific body. What is needed is a taxonomical approach to astronomical object classification with increasingly complex definitions - and the IAU definition itself could be allowed to one of them.
1. World - a body that is massive enough to enter hydrostatic equilibrium but lacking mass sufficient to undergo nuclear fusion at its core.
2. Planet - a world orbiting a star.
3. Moon - a world orbiting a planet
The above excluded what are now called "rogue planets" from being planets since they aren't orbiting a star, but rogue world isn't too detached. Phobos and Deimos would no longer be considered moons under the above - they are merely satellites.
Moving to the more specific: "Classical Planet" - A planet visible to the naked eye (Mercury, Venus, Mars, Jupiter, Saturn). "Major Planet" - A planet which is the dominant body in it's orbital path, meaning it has more than 99.99% of all mass in the path or other objects in that amount are in tight orbit around it (earth/moon). "Dwarf Planet" - A planet which is not the dominant body in its orbital path.