Comet (noun)

1. A celestial object consisting of a nucleus of ice and dust and, when near the sun, a "tail" of gas and dust particles pointing away from the sun.
2. A celestial object consisting of a small body of ice and dust that orbits the sun, typically having a tail that streams away from the sun as it warms up.

Origin:

Middle english: from old french, from latin cometa, from greek komētēs "long-haired star", from komē "hair".

Examples:

1. The comet was visible in the night sky for several weeks.
2. The comet's tail was pointing away from the sun as it moved in its orbit.
3. Comets are believed to be leftovers from the formation of the solar system.
4. The comet was observed by astronomers for several months as it approached the sun.
5. Halley's Comet is visible from Earth every 75-76 years.