This day is also called the Day of Separation.
It has come 6 times in the Qura’n (1). It has come once in verse 17 of Surah Naba that says:
“Verily the Day of Decision is a fixed time.”
This is a very meaningful explanation that explains the separations of that Day: The separation of the Truth from falsehood, the distinction between and the separation of the believers from the ranks of the disbelievers, the separation of brother from brother, the separation of parents from their children and the result of the good doers from those of the evil doers.
This term is often used as “Yom-ol-Qazaa” because the judge (Qadi) terminates the disputes on the day of his judgment so the judgment and disputes are called “Al fadl” because it is the cause of termination of disputes.