According to Space Daily, the IAU definitions of objects in our solar system can be best described this way:
The International Astronomical Union has decided that, to be called a planet, an object must have three traits. It must orbit the sun, be massive enough that its own gravity pulls it into a nearly round shape, [...]

The IAU decided today that our beloved tenth planet will not be defined as a planet. In fact, Pluto has been stripped of its planetary title as well. It’s a sad day here.

The IAU is proposing the following definition of a planet, which would make our beloved tenth planet, really the 12th planet!
A planet is a celestial body that (a) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape, and (b) is in orbit around [...]

The IAU (International Astronomical Union) will propose a definiton of a planet on August 18, 2006, and a vote on that proposed definiton will take place on August 24, 2006. Such a definition holds the fate of the tenth planet, as well as possibly the fate of Pluto. Are either of them a [...]