com ‧ et /ˈkɒmət, ˈkɒmɪt $ ˈkɑː-/ BrE AmE noun [countable]
[ Date: 1100-1200 ; Language: Latin ; Origin: cometa , from Greek kometes 'long-haired, comet' , from kome 'hair' ; because of its long tail ]
an object in space like a bright ball with a long tail, that moves around the sun:
Halley’s comet