Av (also Menachem Av,[2] Hebrew: אָב, Modern: ʾAv, Tiberian: ʾĀḇ) is the eleventh month of the civil year and the fifth month of the ecclesiastical year on the Hebrew calendar.

The Babylonian Talmud states that "when we enter [the month of] Av, our joy is diminished".

However, the month also contains a holiday called Tu B'Av which was, in ancient times, considered one of the happiest days of the year.

[5] Others derive the name of the month from the Hebrew word "Av" - "father".

The name Ab appears in Aramaic ostraca from the Persian period,[8] in Aramaic documents from Ancient Egypt and Palmyra, in Masada and Qarnayim ostraca, in the best manuscripts of Targum Jonathan to Ez.