That is understandable, but not quite right.
Kaddish is fundamentally a prayer of praise
Britannica defines Kaddish as a doxology, a hymn of praise to God, usually recited in Aramaic at the end of major sections of synagogue services.
That is the first fact to keep straight. Even when mourners recite Kaddish, the text itself does not dwell on death. It magnifies God's name.
It became associated with mourning over time
Britannica explains that Kaddish eventually became the prayer of mourners because of its connection to the messianic age and resurrection. Chabad similarly stresses that the prayer is praise, even in its mourner's form.
This is why Kaddish can feel so striking. A grieving person does not recite a lament only. They publicly uphold praise.
The prayer is communal
Kaddish belongs inside a communal prayer setting, not only because of custom but because Jewish mourning itself is communalized. Grief is carried in public language and public rhythm.
Why it still matters
Kaddish still matters because it gives mourners a disciplined form that neither denies grief nor reduces prayer to grief alone. It keeps memory, praise, and community in one frame.
The shortest accurate answer
Kaddish is a Jewish prayer of praise recited in Aramaic, especially known through its mourner's form, though its main theme is the sanctification of God's name rather than death itself.