Asteroids are the small(mostly but occasionally very big) chunks of rocks that have been chipped from other planets. These are mostly found in between the orbits of Mars (Fourth Planet from the sun) and Jupiter (Fifth Planet from the sun).

Definitions of Asteroid. * Any of the thousands of small rocky objects that orbit around the Sun, most of them between the orbits of Mars and Jupiter (although some pass closer to the Sun that Earth does and others have orbits that take them well beyond Jupiter). The largest asteroid is one called Ceres; it's about as wide as the state of Texas. * A small solar system object in orbit around the sun composed mostly of rock. Many of these objects orbit the sun between Mars and Jupiter. Their size can range anywhere from 10 meters in diameter to almost 1000 kilometers. * One of thousands of very small members of the solar system orbiting the Sun between the orbits of Mars and Jupiter. Asteroids are often referred to as "minor planets." * one of a number of objects ranging in size from sub-kilometer to about 1,000 kilometers, most of which lie between the orbits of Mars and Jupiter; also called "minor planets". www.namnmeteors.org/appendixE.html * An interplanetary body, of varying size not associated with a fixed orbit * A small rocky body that orbits a star. Over 100,000 asteroids orbit the sun. * Enormous rocks or boulders that revolve around the sun, usually between the orbits of Mars and Jupiter. * small, rocky body in orbit around the Sun www.nofs.navy.mil/festsci/glossary.html * Small, rocky world. Most asteroids are between the orbits of Mars and Jupiter. See Asteroid, Comet and Meteor Facts page. * Large piece of rock orbiting the sun, usually located in the asteroid belt between Mars and Jupiter. * An object orbiting the Sun that is smaller than a major planet (tens of meters to about 1,000 km diameter), but shows no evidence of an atmosphere or other types of activity associated with comets. Most asteroids are located in a belt between Mars and Jupiter from 2.2 to 3.3 AU from the Sun. * one of the small planets occupying orbits mainly between Mars and Jupiter. tooter4kids.com/space/vocabulary.htm * A rocky or metalic body, orbiting the Sun between Mars and Jupiter, and leftover from the formation of the solar system [LCOTE] * Any of the thousands of small planets or Minor Planets. * A small, rocky planetary body orbiting the Sun. Asteroids are numbered in the tens of thousands. Most are located between the orbit of Mars and the orbit of Jupiter. Their diameters range downward from 1000 km. Compare to meteorite. * small celestial body composed of either metal, rock, ice, or any combination of the above. www.dp9.com/Worlds/jc_glossary.htm * Also ("planetoid") These are rocky bodies, the vast majority of which orbit the Sun between Mars and Jupiter. It is thought that there must be around 100,000 in all. The largest asteroid is Ceres which has a diameter of 579 miles. The smallest detected asteroids have diameters of several hundred feet. Together with comets and meteoroids, asteroids make up the minor bodies of the solar system. They are considered to be left over planetesimals from the formation of our solar system. ... * a medium-sized rocky object orbitting the sun (also known as a minor planet or planetoids) * One of thousands of small planets between Mars and Jupiter with diameters from a fraction of a mile to nearly 500 miles. * Any one of the thousands of bodies in space ranging in size from large boulders to miles in diameter which orbit the sun in a region known as the asteroid belt. The asteroid belt lies between the orbits of mars and Jupiter. To date, over two thousand of these bodies have been identified and catalogued. The largest asteroids are Chiron, Astraea, Juno, Vesta, Pallas and Ceres. * A small, rocky body that moves in an elliptical orbit around the Sun. They are too small to have atmospheres, and occasionally fall to Earth as Meteorites. On January 1, 1801, an Italian astronomer, Giuseppe Piazzi, became the first person to discover an asteroid which was later named Ceres. * a small body in the solar system, ussually moving around the sun between the orbits of Mars and Jupitor. Asteroids are rocky and have irregular shapes. The largest could be about 1000km in diameter and as small as 1km or less. * a rock that moves on an orbit until it collides with another object * A small body orbiting the sun ranging in size from 10 metres to 1000 kilometres in diameter. A meteor or asteroid impact on Earth would likely be cataclysmic. * Large solid mass suspended in outer space that revolves around the sun. Asteroids are larger than meteoroids. * shaped like a star * any of numerous small celestial bodies composed of rock and metal that move around the sun (mainly between the orbits of Mars and Jupiter) * An asteroid is a small, solid object in our Solar System, orbiting the Sun. An asteroid is an example of a minor planet (or planetoid), which are much smaller than planets. Most asteroids are believed to be remnants of the protoplanetary disc which were not incorporated into planets during the system's formation. Some asteroids have moons. The vast majority of the asteroids are within the asteroid belt, with elliptical orbits between those of Mars and Jupiter. * Asteroid 3163 Randi was discovered on August 28, 1981 by Charles T. Kowal at Palomar Observatory, California. It has an orbital period of 3 years, 257 days and is a Mars-crosser asteroid. http://www.google.com/search?hl=en&client=firefox-a&channel=s&rls=org.mozilla:en-US:official&defl=en&q=define:Asteroid&sa=X&oi=glossary_definition&ct=title

Asteroids, also called minor planets or planetoids, are a class of astronomical object. The term asteroid is generally used to indicate a diverse group of small celestial bodies that drift in the solar system in orbit around the Sun. Asteroid (Greek for "star-like") is the word used most in the English literature for minor planets, which has been the term preferred by the International Astronomical Union; some other languages prefer planetoid (Greek: "planet-like"), because it more accurately describes what they are. In late August 2006, the IAU introduced the term "small solar system bodies" (SSSBs), which includes most objects thusfar classified as minor planets, as well as comets. At the same time they introduced the term dwarf planet for the largest minor planets. This article deals specifically with the minor planets that orbit in the inner solar system (roughly up to the orbit of Jupiter). For other types of objects, such as comets, Trans-Neptunian objects, and Centaurs, see Small solar system body. The first asteroid to be discovered, Ceres, is the largest asteroid known to date and is now classified as a dwarf planet. All others are currently classified as small solar system bodies. The vast majority of asteroids are found within the main asteroid belt, with elliptical orbits between those of Mars and Jupiter. It is thought that these asteroids are remnants of the protoplanetary disc, and in this region the incorporation of protoplanetary remnants into the planets was prevented by large gravitational perturbations induced by Jupiter during the formative period of the solar system. Some asteroids have moons or are found in pairs known as binary systems.

Also called planetoid, or minor planet, small body orbiting the sun. More than 10,000 asteroids have orbits sufficiently well known to have been cataloged and named; thousands more exist. Most asteroids are irregularly shaped, unlike the spherically shaped major planets. The largest asteroids, Quaoar (diameter c.800 mi/1,300 km) and Ixion and Varuna (both c.750 mi/1,200 km), reside in the Kuiper belt (see comet comet [Gr.,=longhaired], a small celestial body consisting mostly of dust and gases that moves in an elongated elliptical or nearly parabolic orbit around the sun. ..... Click the link for more information. ) and are about half the size of Pluto. The origin of asteroids is unclear; one theory claims that they were formed from material that could not condense into a single planet because of perturbation effects involving Jupiter. Some asteroids are actually nuclei of comets that are no longer active.