Which term is used for celestial bodies that revolve around the sun in highly elliptical orbit ?

Explanation:

Comet:

Comets are relatively small and icy celestial bodies revolving round the sun. When a comet comes near the sun, some of the 'ice' in it turns into gas. The gas and loose dust, free from ice, create a long illuminating tail that streams behind the comet. 

Asteroid:

These are very small planets or planetoids that are found mainly in a belt between the orbit of Mars and Jupiter. Each asteroid has its own orbit and the orbits of all of them are spread over a large distance, forming a band.

Meteors:

Meteors are pieces of stony or metallic rock widely scattered throughout the solar system. They travel at high speeds around the sun. When meteors come close enough to the earth, they are pulled towards the earth by its gravitational force. As the meteor passes through the earth's atmosphere, it gets burnt due to the immense heat produced by friction with the atmosphere, leaving a brilliant trail of light behind it. Such a meteor is also called a shooting star.