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Śrāddha or Shraaddha (Sanskrit: श्राद्ध) is a Sanskrit word which literally means anything or any act that is performed with all sincerity and faith (Śraddhā). In the Hindu religion, it is the ritual that one performs to pay homage to one’s 'ancestors' (Sanskrit: Pitṛs), especially to one’s dead parents. Conceptually, it is a way for people to express heartfelt gratitude and thanks towards their parents and ancestors, for having helped them to be what they are and praying for their peace. It also can be thought of as a "day of remembrance." It is performed for both the father and mother separately, on the days they became deceased. It performed on the death anniversary or collectively during the Pitru Paksha or Shraaddha paksha (Fortnight of ancestors), right before Sharad Navaratri in autumn.
In practice, the karta (person who performs shraaddha) invites Brahmanaas (individuals who are considered to be very noble, worthy, knowledgeable, etc.) that day, imagines they are his/her parent, performs a homa, serves them with sumptuous food,and treats them with all hospitality and finally serves “pinda pradaana”. (pinda—balls made of rice, given as offerings to the Pitṛs). The Karta then gives "dakshina" (fees) to the brahmanaas. (There are various other actions done to show respect to the Brahmanaas, like washing their feet etc. during the course of shraaddha). Crows are also considered ancestors in Hindiusm and during Śrāddha the practice of offering food or pinda to crows is still in vogue.
Since this is one of the most important and noble “Saṃskāras” (rituals meant to cleanse the mind and soul) that the Hindu sages have envisaged, it is imperative that the performer of the ritual understands what he or she is doing. Only then will the true intent of the ritual be fulfilled and the performer of the ritual feel completely gratified. Else, the ritual becomes just a mechanical exercise for one’s part.
The Shraadha period 
In Hindu amanta calendar ( ending with amavasya ), second half of the month Bhadrapada is called Pitru Paksha: Pitripaksha or Shraddha paksha and its amavasya ( new moon ) is called sarvapitri amavasya. This part is considered inauspicious in muhurtshashtra (electional astrology). At this time (generally September) crops in India and Nepal are ready and the produce is offered as a mark of respect and gratitude (by way of pinda) first to the ancestors be they parents or forefathers before other festivals like Navaratri begin.
See also 
- Shraaddha, R. K. Srikanta Kumaraswamy, IIT, Chennai. In the Kannada language
- Online Course for Basic Vedic Mantras,Shraaddha & Tharpana rituals for Brahmins Online Vedic Courses to learn from Home
- Sraddha in www.britannica.com