UNIVERSEH: The European Space University

Short definition: A meteoroid is a small rocky or metallic body in space that has not yet entered the Earth's atmosphere. When a meteoroid enters the Earth’s atmosphere at a high speed and burns up, it leaves a glowing trail, which is called a meteor.

Detailed definition: Meteoroids are defined as objects significantly smaller than asteroids, ranging in size from grains to objects up to a meter wide. Objects smaller than meteoroids are called micrometeoroids or space dust. Most meteoroids are fragments from comets or asteroids, containing extraterrestrial nickel and iron.
When meteoroids enter the Earth’s atmosphere at a high speed (usually over 20 km/s), due to aerodynamic heating they leave a glowing trail, which is widely known as a “shooting star”. This phenomenon is called a meteor. If a meteoroid survives its passage through the Earth’s atmosphere and lands on the surface, it’s called a meteorite.

Etymology: Meteoroid comes from meteor + -oid. -oid is a suffix coming from Ancient Greek εἶδος (eîdos, “form, likeness”), which means “resembling; having the likeness of”.

Sample sentence(s): It was found that meteoroids from cometary sources were typically of porous, aggregate compositions with relatively low densities. (Source: Cambridge English Corpus | Cambridge University Press | ELT. (n.d.). https://www.cambridge.es/en/)

Translations:

French: Météoroïde

German: Meteoroid

Italian: Meteoroide

Polish: Meteoroid

Swedish: Meteoroid