In the context of offering piṇḍa (pinda; the sanctified food-ball offered to the spirits of the dead) to please all, it is mentioned that the piṇḍa should be offered, and tarpaṇa (water-offering) should be performed, dedicated to the gotra-pravara (chief of the clan) as well as to āmagarbha (amagarbha). Āma means unripe or immature. So āmagarbha refers to the immature foetus, which has been destroyed in the mother’s womb before being born. Offering piṇḍa to ‘āmagarbha‘ means a ritual offering made to this kind of unripe foetus–
virūpā āmagarbhāśca jñātajñātāḥ kule mama
teṣāṁ piṇḍo maya datto akṣayyamupatiṣṭhatām.