An Article In Meteorite-Times Magazine
by Robert Verish

From Asteroids to Meteoroids to Meteors to Meteorites

Guess what? The International Astronomical Union (IAU) originally defined the word "meteor" to be used as BOTH the term for the solid object, as well as, the light-phenoma that it produces.


For years I've been told that the term "meteor" only applies to the light phenomenon that we see high in the night sky, but not to the physical object that is falling from space. I was told that the International Astronomical Union (IAU) convened a committee titled "Commission 22" back in 1961 to officially define the terms for all of these meteoric objects, such as meteoroids, meteors, and meteorites.

And for years I've known that the continuum from asteroid to meteorite includes the interim transition of meteoroid to meteor. But I eventually discovered that, according to the Commission 22 definition, the term "meteoroid" cannot be applied to the physical object that produces a meteor. Only as long as a solid object is orbiting in interplanetary space, can it be called a "meteoroid". Hence, the word "meteoroid" could not be used for that same object while it is moving through the atmosphere, which produces the meteor phenomenon.

So these narrowly defined terms for "meteor" and "meteoroid" resulted in there being no officially-approved word for the solid particle that produces the meteor light phenomenon. At least, that appeared to be the case to me. That is, until recently, when I read the original IAU definition for "meteor". It appears that Commission 22 had originally intended that there be a broader definition for the term "meteor" that included the physical object, as well as, the light phenomenon which it produces. See below:

Definition of terms by the IAU Commission 22, 1961.

A. meteor:
in particular, the light phenomenon which results from the entry into the Earth's atmosphere of a solid particle from space; more generally, as a noun or an adjective, any physical object or phenomenon associated with such an event.
B. meteoroid:
a solid object moving in interplanetary space, of a size considerably smaller than an asteroid and considerably larger than an atom or molecule.
C. meteorite:
any object defined under B which has reached the surface of the Earth without being completely vaporized.
D. meteoric:
the adjectival form pertaining to definitions A and B.
E. meteoritic:
the adjectival form pertaining to definition C.
F. fireball:
a bright meteor with luminosity which equals or exceeds that of the brightest planets.
G. micrometeorite:
a very small meteorite or meteoritic particle with a diameter in general less than a millimeter.

Where do we go from here?
From here on we need to embrace the [original] concept, as defined by the IAU, that a meteor is BOTH the physical object that enters into the Earth's atmosphere, as well as, the light phenomenon that it produces.
Here is a link to a website for
IAU Definitions, that can be used as a reference for details on terms and terminology.


Relative size of this solar system's planets and planetismals.

If you have any questions relating to theNaming of Minor Planets or Small Body Nomenclature, you can submit your terminology questions to

IAU - Naming Astronomical Objects


UPDATE (2012-08-20):

"Meteorite and meteoroid: New comprehensive definitions"

  1. Alan E. RUBIN1,*,
  2. Jeffrey N. GROSSMAN2

Article first published online: 26 FEB 2010

Meteoritics & Planetary Science

Meteoritics & Planetary Science

Volume 45, Issue 1, pages 114122, January 2010

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