It is not a one-time funeral prayer. It returns.
Yizkor is a memorial service
Britannica defines yizkor as the memorial prayer service recited for the dead by Ashkenazi Jews. The prayer takes its name from its opening request that God remember the soul of the deceased.
That basic definition matters because Yizkor is not simply generic remembrance. It is a recurring ritual of memorialization.
It is said several times a year
Britannica notes that Yizkor is recited four times annually: on Yom Kippur, on the last day of Passover in the diaspora, on Shavuot, and on Shemini Atzeret.
This repetition gives the service its force. Grief is not confined to the anniversary of death. The calendar itself carries it forward.
The service places memory inside communal worship
Yizkor happens in synagogue, as part of a public liturgical framework. That means mourning is not treated as merely private feeling. The dead remain present within the community's sacred time.
Why it still matters
Yizkor still matters because it gives Jews a disciplined way to remember the dead without requiring grief to disappear or to dominate every day. The memory returns at appointed times.
The shortest accurate answer
Yizkor is the Jewish memorial prayer service for the dead, recited on Yom Kippur and certain major festivals during the year.