Translated literally, the phrase means "the event triggering the inheritance", which is always the death of a natural person (sec. 1922 (1) of the German Civil Code). Hence, we recommend using the word "death" as the best translation but with a parenthetical containing the phrase "the event triggering the inheritance / devolution of the estate)" when you first encounter the term.
There are multiple definitions - click on the translation that matches your context.
a time when someone dies (=no longer lives)
There were three deaths in the family last year.
the state of being dead (=of no longer living)
He was stabbed to death with a sword.