Relating to, resembling, or characteristic of a comet or comets.
From Latin 'cometarius', derived from 'cometa' (comet), which itself comes from Greek 'kometes' (hairy), because comets' tails resemble hair. The English adjective has been in use since the 17th century.
The ancient Greeks literally called comets 'hairy stars' because their tails looked like flowing hair—it's poetic astronomy that reminds us our ancestors saw the sky with imagination, not just instruments.
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