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As an astronomer that works on planet formation, I think that ad-hoc dynamical definitions (both yours and that of the IAU) are a terrible idea and a waste of everyone's time. The names of things should tell you something about what they are:

• Starts are bodies that undergo fusion (or at least did some at some point).

To classify bodies around stars, you could consider the steps to forming a planet:

• When a star is young it is surrounded by a disk of gas and dust.
• Dust forms 1-100 km bodies. Call them planetesimals, asteroids, KBOs, comets, etc.
• Planetesimals collide due to gravitational interactions and from Mars-size bodies that we call planetary embryos.
• Embryos can collide with each other as well, though on a different timescale, and that produces rocky planets like the Earth and Venus.
• Separately, large bodies may, under certain conditions, also grow rapidly through the accretion of cm-size pebbles. It is likely that the massive cores of the giant planets formed this way.
• If the core gets massive while gas is still present, it can accrete a large gas envelope around 10% of the planet's mass, and that gives you an ice giant like Uranus and Neptune.
• Under certain conditions, the planet can enter a runaway accretion of gas and instead produce a true gas giant like Jupiter and Saturn.

Therefore, based on what the bodies actually are and how they form:

• Asteroids and comets are planetsimals.
• Mars is an Embryo.
• Venus and Earth are another type of body; call it a rocky planet.
• Uranus and Neptune are another type of body; call it an ice giant.
• Jupiter and Saturn are another type of body; call it a gas giant.

I dislike the term "planetary embryo" because it implies that the body is destined to accumulate additional material and "grow up" to be a rocky planet (or something larger). That's only one of several possibilities.

Hello u/Afraid_Success_4836, your submission "My (still kinda WIP) planet definition" has been removed from r/space because:

• Such questions should be asked in the "All space questions" thread stickied at the top of the sub.

Please read the rules in the sidebar and check r/space for duplicate submissions before posting. If you have any questions about this removal please message the r/space moderators. Thank you.

Yeah. I'm just summarizing the science. The OP (and you) are invited to come up with different words. The point is that there are roughly five types of bodies that orbit a star that themselves are not a star:

• Bodies similar to asteroids, comets and KBOs
• Bodies similar to Mars
• Bodies similar to Earth and Venus
• Bodies similar to Uranus and Neptune
• Bodies similar to Jupiter and Saturn

The interested reader is welcome to assign them names if they wish.

My dynamical definition kinda works together with more physical definitions (based on size and composition).