The Next Day
Next Day, The Following Day
noun
The following day is the day coming the day you're talking about. It's the next day.
よくじつ
This is a jukugo word, which usually means on'yomi readings from the kanji. If you know the readings of your kanji you'll know how to read this as well.
列車は翌日平常運転に戻りました。
The railroad service went back to normal the next day.