Date: July 18
Tisha B’Av, the ninth day of the month of Av, is the major day of communal mourning in the Jewish calendar. This day commemorates the destruction of the First and Second Temples in Jerusalem in 586 B.C.E. and 70 C.E., respectively, and is observed by fasting.
A three-week period of low-level mourning leads up to the holiday of Tisha B’Av, representing the final siege of Jerusalem that led to the Second Temple’s destruction. During this time, it is traditional to avoid any public celebrations, and many traditional men refrain from shaving, reflecting the practice during personal mourning periods.
The last nine days of Tisha B’Av is a period of deeper mourning, as well as avoiding meat and practicing the signs of mourning that may not have been practiced earlier in the mourning period.
The actual day of Tisha B’Av is an intense day of mourning, with practices similar to those of Yom Kippur. This day is observed by fasting, refraining from washing, visiting cemeteries and a reading of the book of Lamentations in synagogue.
Pronunciation: TISH-uh BAHV
Alternate spellings: Tish’a B’Av
Tisha B’Av 101, MyJewishLearning.com
Glossary of Jewish Terminology, Judaism 101, jewfaq.org