Wiktionary
deathday
n. date of (someone's previous) death; anniversary of (a) death.
Usage examples of "deathday".
Till his deathday he held the Castle of the Scaur, and cleansed the Wood Perilous of all strong-thieves and reivers, so that no high-street of a good town was safer than its glades and its byways.
In fact, never again till deathday were they to even utter so much as a syllable about the affair.
The nearest thing to it Harry had ever heard was the ghost orchestra at Nearly Headless Nick's deathday party, who had all been playing the musical saw.