אָב I, (Assyr. A-bu, Schr. K. A. T., p. 247) Ab, the fifth month of the Jewish calendar (of thirty days) beginning between the eighth of July and the seventh of August, and ending between the sixth of August and the fifth of September. R. Hash. I, 3, על אב וכ׳ for announcing the beginning of Ab messengers are sent out, for the sake of the fast. Ib. 18ᵇ ט׳ באב the ninth of Ab, anniversary of Temple destruction. Taan. IV, 6 משנכנס אב with the beginning of Ab. Ib. 29ᵇ לישתמיט מיניה באב let him try to be relieved of (the law-suit) in Ab. Meg. 5ᵇ; a. e.