Shloshim (thirty) is the thirty-day period counted from burial, the second and lighter stage of Jewish mourning after the intense first week of shiva. During it the mourner returns to work and ordinary life but continues to abstain from festive gatherings, music and celebration, and, for a parent, from cutting the hair or shaving. For most relatives mourning ends with the thirtieth day; for a father or mother it continues in a still lighter form for a full twelve months, during which the mourner's Kaddish is customarily said. The graded structure, the sharp restriction of shiva easing into shloshim and then, for parents, into the year, reflects a considered understanding of grief as something that recedes in stages rather than ending at once, giving the bereaved a defined path back into ordinary life while keeping the loss marked for a measured time.
The thirty-day unit itself has scriptural precedent: the Torah records that Israel mourned both Aaron and Moses for thirty days (Numbers 20:29, Deuteronomy 34:8), a period later halakhic tradition generalized into the standard shloshim observed for other relatives. A widely followed custom limits the extended mourning for a parent, and the recitation of the mourner's Kaddish, to eleven months of the twelve rather than the full year, reasoning, as later authorities explain it, that reciting Kaddish for the maximum traditional period would imply the deceased required the harshest possible measure of post-mortem judgment, an implication mourners are traditionally careful to avoid making even inadvertently.