What is the meaning of blood money (Diyya), and who are the 'Aqilah (male relatives on the father's side) of a woman upon whom the Diyya is incumbent when she accidentally kills her child?

Diyah (blood money) is the money required for killing a free human being as compensation for his blood, or the money required for an offense against a free human being, whether it involves life or lesser injuries. The 'Aqilah (male agnates) are the relatives of a person from his father's side. They pay the diyah for accidental killing in installments over three years, and its approximate amount is 4250 grams of gold. If the 'Aqilah are unable to pay, it is paid from the public treasury (Bayt al-Mal); and if that is not available, then from the killer's own money. The diyah is waived if the guardians of the child, who are entitled to it (excluding the one who caused the killing), forgive it.