In astronomy,

  • A meteoroid is what it is called before it enters a planet's atmosphere,
  • A meteor is what it is called after it enters a planet's atmosphere but before it hits the surface, and
  • A meteorite is what it is called after it impacts the planet's surface.

The Question

Is there, or has there ever been, a -eor and -eorite analogue for asteroid? Like, say, just for an example, asteror or asterite?

(I looked on the OED and found out that asterite is in fact a word; but it doesn't mean what I'm looking for, or if it does, then it doesn't display that definition.)


  • 3
    I think these words don't exist because asteroids don't normally enter the atmosphere. – herisson Oct 22 '15 at 21:56
  • 1
    Can you cite your definitions of "meteoroid" and the like? I've found conflicting information about how these terms are defined. – herisson Oct 22 '15 at 22:07
  • 1
    No, there are no such analogous words. An asteroid out in space as it enters the earth atmosphere is still called an asteroid, and as it hits the ground it is also called an asteroid. – Mitch Oct 22 '15 at 22:10
  • Asteroids on a interception trajectory with Earth (that could potentially crash on it) are called "geocruisers". Happily, collision never occured. – Graffito Oct 22 '15 at 22:10
  • @sumelic: They don't normally enter the atmosphere. But they do sometimes, as evidenced by the fact that the dinosaurs are extinct. – SarahofGaia Oct 22 '15 at 23:15

There seem to be different opinions on how to define meteoroid. One big difference between meteoroids and asteroids is that asteroids don't regularly enter the atmosphere. So there's no real need for special words to describe an asteroid in the atmosphere and after impact.

For ("small") asteroids that do impact, NASA actually says that they can be called "meteorites."

The main criterion for distinguishing meteoroids from asteroids appears to be size. Wikipedia's article on "Impact event" uses the criterion that meteoroids are "Objects with a diameter less than 1 m (3.3 ft)." Other sources that I've found describing the difference:

The official definition of a meteoroid from the International Astronomical Union clearly brings out the distinction between meteoroid and asteroid: A meteoroid is a solid object moving in interplanetary space, of a size considerably smaller than an asteroid and considerably larger than an atom.

Both asteroid and meteoroid refer to bodies in our solar system that orbit the Sun but are not large enough to be deemed planets. Traditionally, anything smaller than ten metres across was called a meteoroid.


In space, a large rocky body in orbit about the Sun is referred to as an asteroid or minor planet whereas much smaller particles in orbit about the Sun are referred to as meteoroids. Once a meteoroid enters the Earth's atmosphere and vaporizes, it becomes a meteor (i.e., shooting star). If a small asteroid or large meteoroid survives its fiery passage through the Earth's atmosphere and lands upon the Earth's surface, it is then called a meteorite. [bolding added]

NASA's Near Earth Object Program FAQ

An asteroid is a solid body in Space, smaller than a planet but large enough to be seen at a distance.

A meteoroid is a solid body in Space, too small to be seen at a distance, which is discovered when it strikes something (such as the atmosphere of a planet or the surface of another body), causing a momentary flash of light (a meteor) or other disturbance in whatever it strikes, or after it makes a crater or deposits meteoritic material.

–"Meteoroids vs Asteroids", by Jeff Root, at Jeff's Space and Science Pages hosted by the Minnesota Space Frontier Society

(The above seems to be the author's advocated definition, rather than a single established definition.)

  • So like this, then, right? – SarahofGaia Oct 23 '15 at 3:50
  • @SarahofGaia: Um, I guess so... (I actually had a tough time interpreting that chart, but I think I got it!) The only difference is that I didn't actually ever answer your question about the equivalent to "meteor" for an asteroid, because the citation I found from NASA only talks about meteorites. Presumably this extends to "meteor" as well, though. – herisson Oct 23 '15 at 3:52
  • Well, what about this? – SarahofGaia Oct 27 '15 at 2:54
  • (And it's fine. I would presume the same, I think.) – SarahofGaia Oct 27 '15 at 2:54

The equivalent word is aster which meant 'star' in Ancient Greek. Nowadays in English, it only refers to a star shaped flower.

The suffix -oid simply means 'like'.

An asteroid is like a star.

  • Your answer has some value, but it puts too much emphasis on a literal interpretation of etymology. – SarahofGaia Oct 22 '15 at 23:20
  • At least in terms of the suffix -oid. – SarahofGaia Oct 22 '15 at 23:21
  • You were pretty reasonable regarding the root aster. – SarahofGaia Oct 22 '15 at 23:21
  • 1
    @SarahofGaia - Your question is open to interpretation. I gave the lexical analogue. Presumably then you are interested only in the astronomical analogue. (?) – chasly - supports Monica Oct 22 '15 at 23:30
  • I thought that was clear considering it's an astronomical term. – SarahofGaia Oct 26 '15 at 17:39

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