Traditional Judaism delineates a series of steps, beginning with the moment of death, as follows:
Aninut, a Hebrew word meaning "deep sorrow," is a legal category of mourning used to designate the period from death to burial. An individual who has lost a loved one is referred as an Onen during this time.
Are there any special requirements of an Onen?
Quite the contrary. Jewish tradition recognizes that the enormous pain and shock of loss must be respected. Accordingly, an onen is freed from the responsibility of performing any positive Mitzvot (except observing the Shabbat), such as reciting the Shema or putting on Tefilin.
In addition, even close friends are instructed not to express condolence but rather to wait until after the interment. That is why it is only as the family leaves the cemetery that friends are first allowed, by tradition, to utter the traditional words of comfort: "May the Almighty comfort you among all the other mourners of Zion and Jerusalem."
Avelut, a Hebrew word meaning "lamenting," refers to the mourning period following interment. A mourner during this period is called an avel. Avelut, which follows aninut, encompasses the mourning customs of shivah, sheloshim, and, when a parent has died, the entire twelve-month mourning period.