What is the mourning period (iddah) for a widow, and what are her rights during it?

A widow's iddah (waiting period) after her husband's death is four lunar months and ten days (Surah Al-Baqarah 2:234), or until she delivers if she is pregnant, whichever is longer. During this period she generally observes ihdad (mourning) — avoiding remarriage, adornment/perfume, and generally staying in the marital home unless there's a genuine need to leave — as a mark of respect for the marriage and to establish clarity about paternity should she be pregnant.

During iddah, a widow retains the right to remain in the marital home (where practically possible) and is entitled to her share of her late husband's estate as an heir (see Q4) once that estate is properly settled, alongside anything already owed to her such as unpaid mehr. Unlike the iddah after divorce, a widow is not entitled to nafaqah (maintenance) from her husband's estate during this period specifically because he is no longer alive to provide it, though her inheritance share and any deferred mehr are separate matters that should be settled for her.

Source: Quran 2:234 (widow's iddah duration); general Sunni fiqh on ihdad (mourning) and a widow's rights during iddah.