asteroid: a minor planet (with a diameter between 1 km and several hundred kilometres), especially in the inner Solar System (between Mars and Jupiter)
meteor: a streak of light that is seen when a meteoroid enters Earth’s atmosphere; often called a ‘shooting star’ or a ‘falling star’
meteorite: a meteoroid that falls to Earth’s surface
meteoroid: a solid body travelling through space that is smaller than an asteroid; mostly the remnants of comets or asteroids. When a meteoroid enters Earth’s atmosphere, heating results in its becoming visible as a meteor