The twelve sons born to Kashyapa and Aditi were called Dwadashadityas. They are Dhata, Mitra, Aaryama, Rudra, Varuna, Surya, Bhaga, Vivasvan, Poosha, Savita, Twashta, Vishnu. In addition, Aditi had 21 children. They are all known as Aadityas. From Aditi’s thirty three sons, the 33 crore gods emerged. The eldest among the sons was Indra and Vamana was the youngest, as per Mahabharata Adiparva Chapter 66 verse 36 and Ramayana Aranyakanda Sarga 14 verse 14.

Though we use Aaditya mainly for Surya, there are many aadityas as per Rigveda, chief among whom was Varuna. Though the names of the adityas now serve as alternate names for Surya, in the vedic period, they were separate gods. Also, many devas who are reduced to the role of digpalakas now – Indra, Agni etc were the main gods in the vedas. The adityas have been absorbed into Surya’s identity, Maruttas to Vayu, and Rudra to Shiva, as per Rigvedasamhita (Sardar K M Panicker’d foreword)