Ab (month of year).

(אך, ‘ābh): The name of the fifth month in the Hebrew calendar, the month beginning in our July. The name does not appear in the Bible, but Josephus gives it to the month in which Aaron died (Ant., IV, iv, 6; compare Num 33:38).

[ISBE]

AB
1. Father, found in many compound Hebrew proper names: as Abner, father of light; Absalom, father of peace.
2. The fifth month of the sacred, and the eleventh of the civil year among the Jews. It began, according to the latest authorities, with the new moon of August. It was a sad month in the Jewish calendar. On its first day, a fast was observed for the death of Aaron, Nu 33:38; and on its ninth, another was held in memory of the divine edicts which excluded so many that came out of Egypt from entering the promised land; and also, of the overthrow of the first and second temple. See MONTH.

[Amtrac]