What does こたつ mean?
こたつ is a Japanese noun meaning “table with heater, (originally) charcoal brazier in a floor well” in English. It is written as こたつ in hiragana, and kotatsu in romaji. This word is part of JLPT N1 vocabulary.
Example sentence
こたつで寝ちゃったら風邪引くのはあたりまえ。自己管理がなっていない。
Of course you'll catch a cold if you fall asleep under the kotatsu. You have to learn to take care of yourself.