Shaʽban (Arabic: شَعْبَان, Šaʿbān) is the eighth month of the Islamic calendar. It is called the month of "separation", as the word means "to disperse" or "to separate" because the pagan Arabs used to disperse in search of water. The fifteenth night of this month is Mid-Sha'ban, which coincides with the celebration of Shab-e-Barat in Muslim communities all over Asia. Sha'ban is the last lunar month before Ramadan, and so Muslims determine in it when the first day of Ramadan fasting will be. In the second Hijri year (624), fasting during Ramadan was made obligatory during this month.
https://en.wikipedia.org/wiki/Sha%27ban