The question most likely refers to the "KAH-dish", a short prayer recited at one or two points in each synagogue service by individuals in mourning for a parent, child, sibling or spouse.
Interestingly, the Kaddish makes no mention of death whatsoever. It is entirely a soaring praise of the Master of the Universe, and a call to others to praise His name. It has been suggested that He is the one who feels most deeply the loss of one of His creations, and the Kaddish is our way of consoling the Creator on His loss.