古こ潭たんこたんMeanings1nounold abyss; ancient deep poolrare termRare literary term for a deep, old pool or abyss, often with a classical or poetic feel. Not used in everyday conversation.その詩しには「古こ潭たん」という言こと葉ばが使つかわれている。The word 古潭 is used in that poem.