The word yahrzeit (יארצייט, pronounced YAHR-zite) literally means "time of year" and refers to the anniversary of the death of a Jew as observed by a mourner. Yahrzeit is always based on the date of death (not burial) according to the Hebrew calendar. Since determining the anniversary of the Hebrew date of death can be tricky in relation to the Gregorian calendar, many synagogues keep registries of the Hebrew dates of members' deaths and send notices reminding the family of the yahrzeit date.
According to the rabbis, on yahrzeit the main halakhic (legal) obligation is to recite the mourner's version of the Kaddish prayer three times (evening, morning, and afternoon) on behalf of the first-relative (mother, father, brother, or sister) who has died. Some people also fast on the day of the yahrzeit.
It is also a minhag (custom) to commemorate the occasion by lighting a yahrzeit candle that will burn throughout the 24-hour day of the anniversary of death (from sunset to sunset). This is linked with the thought expressed in Proverbs 20:27, "The spirit of a person is the lamp of the Lord."
A prayer is often recited when kindling the candle, thanking God for the memory and the good influence of the loved one. After the prayer it is customary to add:
- Zichrono livrachah ("May his memory be for blessing"), or
- Zichronah livrachah ("May her memory be for blessing")
Yahrzeit candles are also lit during Yizkor (memorial services), notably during Yom Kippur and on the last day of each of the three pilgrimage festivals: Pesach, Shavuot, and Sukkot (as well as Yom HaShoah).