Yizkor is a Hebrew word that comes from the root Z-Ch-R - to remember. The specific word is used to refer to the memorial prayer for the dead.
The Yizkor prayer is recited on the following days.
Everybody who has lost a parent, child, sibling or spouse takes part in the Yizkor service, although many people have the tradition of not saying the Yizkor prayer during the first year after the death in case they would become too emotional. In many Synagogues, those people who are fortunate enough not to have to say Yizkor leave the Synagogue, but this is becoming discouraged for three reasons.
- It is very disruptive.
- There are many other prayers said as part of Yizkor (eg a prayer for those who died in the Holocaust and for people who died in the wars and terrorist attacks in Israel).
- There is now a specific prayer of thanks said by those who still have both parents living.
The Yizkor service itself is very popular, and many people who aren't that religious will make a point of coming to the Synagogue for it, especially on Yom Kippur. It is said after Kriat HaTorah.
The service usually only takes about 10 minutes. The Rabbi recites one or two introductory prayers and/or psalms, following which everybody says quietly to themselves the Yizkor prayers they need to say, asking that the souls of their departed relatives be "under the shelter of G-D's presence". The Rabbi then often recites the prayers for martyrs as described above, and then the regular service continues.
Many Synagogues have the tradition on Yom Kippur of reciting a special prayer and reading out the name of every person who has a Yizkor prayer, as Yom Kippur is seen as a particularly important day for these things. However, as congregations age, the list gets longer and longer. Instead, some now publish a booklet listing all the names, so everybody is still recorded and remembered.