What does meteoroid mean?
A meteoroid is a small natural object, usually a piece of rock or metal, moving through space. The word is especially useful because it names the object before it enters an atmosphere. After entering Earth’s atmosphere, a meteoroid may create a bright streak called a meteor; if enough of it survives to reach the surface, the remaining fragment is called a meteorite. Meteoroids can come from comets or from collisions involving asteroids, and some travel in streams that produce meteor showers when they encounter Earth. In general conversation, the term “asteroid” is often used for any small rocky object in space, but technically an asteroid is usually a larger body, while a meteoroid is a smaller fragment. The distinction is central to describing space missions, impact risks, and atmospheric phenomena accurately.
nounA meteoroid is a small natural object, typically a fragment of rock or metal, traveling through space. When it enters Earth’s atmosphere and produces a luminous streak, it is called a meteor; if it reaches the ground, it is called a meteorite.
- A small fragment of rock or metal traveling through interplanetary space, usually as part of a stream or debris from a parent body.
"Astronomers tracked the meteoroid as it approached Earth and calculated its likely impact path."
"The spacecraft detected a tiny meteoroid striking the shield."
"That meteoroid is expected to pass close to Earth during the next month."
The standard plural adds “-s” to the singular form.
"Several meteoroids were detected entering the atmosphere."
A meteoroid becomes a meteor only when it lights up in the atmosphere, and a meteorite only if it survives the journey to the ground.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does meteoroid come from?
The word “meteoroid” was formed in the 19th century by combining “meteor” with the suffix “-oid,” meaning “resembling” or “a form of.” “Meteor” comes through French from the Greek meteoros, associated with things raised high in the air, including atmospheric phenomena. The same Greek root also underlies “asteroid” and “meteorite,” reflecting the historical development of terminology for objects observed in the sky.
Related word forms
How meteoroid is actually used
The term is primarily scientific and distinguishes an object in space from the atmospheric phenomenon called a meteor and the landed object called a meteorite. In everyday language, “space rock” and “asteroid” are sometimes used less precisely.
Easily confused with meteoroid
A meteoroid is generally a smaller piece of space debris, while an asteroid is a larger rocky body orbiting the Sun; the terms overlap in informal usage.
A meteoroid is the object in space, whereas a meteor is the visible atmospheric streak produced when it enters an atmosphere.
A meteoroid is a body traveling through space, while a meteorite is a fragment that has survived passage through an atmosphere and reached the ground.