1. a celestial object made of ice, dust, and rock that orbits the sun and develops a bright tail when approaching the sun
Usage: astronomy

Examples

• Halley’s Comet returns to Earth’s vicinity every 76 years.
• The comet’s tail always points away from the sun.
• We could see the bright comet with the naked eye last night.
• Scientists study comets to learn about the early solar system.
• The comet left a spectacular trail of light across the sky.
• Ancient civilizations often viewed comets as omens.
• This comet won’t be visible again for another century.