1A formal written notice requesting payment (a dunning letter); a reminder sent to a delinquent payer.
家賃の滞納で督促状が届いた。
A dunning letter arrived because I was behind on rent.
督促状を無視すると、さらに手続きが進む可能性がある。
If you ignore a dunning letter, further procedures may follow.
会社はすぐに督促状を送ったが、支払いはまだ行われていない。
The company immediately sent a dunning letter, but payment still hasn't been made.