Definition - What does Sakra mean?
Sakra, also called Shakra, is one of the 12 sons of Aditi who, according to the Vedas, is the mother of the gods. Sakra is a Sanskrit term which means "powerful" or "vigorous." Used as an epithet of Indra, one of the Hindu gods, Sakra is referred to in several Vedic texts. Sakra is worshiped by Hindus, Buddhists and Jains.
Yogapedia explains Sakra
The 12 sons of Aditi are Mitra, Varuna, Aryaman, Daksa (also Daksha or Dhata), Bhaga, Ansha, Tvashtr (Tvashta), Savitr, Pusan (Pusha), Sakra, Vivasvat (Vivasvan) and Visnu (Vishnu). The 12 sons are also referred to as the 12 spokes of the sun's wheel, which represent the 12 months.
An epithet of Indra as a reference to his might, Sakra is mentioned in the "Rig Veda," "Sama Veda" and "Adharva Veda." The name also finds mention in the great epic, the "Mahabharata," as Sakra is the ruler of devas.
In Buddhism, Sakra is considered the lord of devas and, unlike in Hinduism, Indra and Sakra are different deities. Sakra is called Sakra Devanam Indra who rules Trayastrimsa heaven, which is at the top of Mount Meru and is the highest heaven. The deities of this heaven are mortal, hence the passing away of a Sakra will bring the next Sakra to the throne.
In Jainism, Sakra is Lord Indra and in his heavens reside jinas, the spiritual victors.