Godana literally means "shaving the head, chin, lips and other parts of the body, including Śikhā” (tuft on the head). In Chaulam the tuft is exempted from shaving. "Godānam" is a term generally understood as "donation of a cow".
गावः केशाः दीयन्ते खण्ड्यन्ते अत्रेति गोदानम् (दो = अवखण्डने – दिवादि) gāvaḥ keśāḥ dīyante khaṇḍyante atreti godānam (do = avakhaṇḍane – divādi)
"gāvaḥ" means hair. The Saṃskāra in which the hair is completely shaved is called Godānam.
एवं गोदानमन्यस्मिन्नपि नक्षत्रे षोडशे वर्षे (आपस्तम्बगृह्यसूत्रम्, १६.१२) evaṃ godānamanyasminnapi nakṣatre ṣoḍaśe varṣe (Āpastambagṛhyasūtram, 16.12)
Just like in the case of Chaulam the procedure is to be followed (right from Brāhmaṇabhojanam, i.e. feeding Brāhmaṇas, down to Varadāna, i.e. donation of a cow to Brahmā / priest by father). It is to be performed during the sixteenth year (counted from the date of conception) and in auspicious Nakṣatras (stars) such as Rohiṇī.
Godānam has to be performed after the completion of Vedavratas and Snātakam. This Saṃskāra is to be performed by Ācārya. Vivāha samskara follows after Godānam. Keśānta (end of hair) used by Manu (2.65) and Paraskara is a synonym of Godāna. Godāna is performed on girls but silently (Śāṅkhyāyanagṛhyasūtram, 1.28.22).
Time of Performance
Most smrtikaras say that this samskara was performed in the 16th year. According to Shankhayana grhyasutras it may be performed in the 16th or 18th year. There are many versions of views about the starting point from which 16 years has to be calculated.
According to Manu (2.65) keshanta is performed in the 16th, 22nd, or 24th year respectively for a brahmana, kshatriya or vaishya. Laghu Ashvalayana smriti says that Godana may be performed in the 16th year or at the time of marriage.
All sutrakaras agree that godana follows the procedure of Chudakarana with a few differences. Ashvalayana clearly states that Chaula is to be performed in the third year while godana has to be performed in the 16th year.
This samskara went out of vogue, so much that most of the medieval digests like the Smrtichandrika, Samskaraprakasha and Nirnayasindhu hardly contain any details about it.