green comet noun [C] UK /ˌgriːn ˈkɒm.ɪt / US /ˌgriːnˈkɑː.mɪt/ a type of comet (= an object that moves around the sun that is seen on rare occasions from the earth as a bright line in the sky) that has a green glow because of radiation from the sun A green comet that will be … Continue reading New words – 30 January 2023