1A small rocky body orbiting the sun. Large numbers of these, ranging enormously in size, are found between the orbits of Mars and Jupiter, though some have more eccentric orbits.
- Ceres was initially considered to be a planet until other asteroids with similar orbits were found.
- Most of the known asteroids orbit the sun in a belt between Mars and Jupiter.
- These scientists also study the natural satellites of other planets as well as asteroids and comets.
2 Zoology An echinoderm of the class Asteroidea, which comprises the starfishes.
- The asteroid is preserved with the dorsal surface exposed.
- Available morphological data suggest no ecologic parameters that would be unusual among living asteroids.
- An unpaired commonly enlarged interbrachial ossicle, the axillary, occurs in most Paleozoic asteroids, including those treated here.
- Example sentences
- The Hubble Space Telescope captured a picture of starlit asteroidal and cometary debris encircling the yellow dwarf star HD 107146.
- These satellites range in size from small on the asteroidal scales, to nearly as large as Saturn's moon Mimas.
- Our understanding of astronomy has shown us that cometary and asteroidal impacts are relatively commonplace over timescales of hundreds of millions of years.
Early 19th century: from Greek asteroeidēs 'starlike', from astēr 'star'.
For editors and proofreaders
Line breaks: as¦ter|oid
Definition of asteroid in:
What do you find interesting about this word or phrase?
Comments that don't adhere to our Community Guidelines may be moderated or removed.