Aum is the primal creative vibration, the Creative Word, that is behind the manifestation of the physical world. Yogananda calls it “the vibration of the Cosmic Motor” (162).

An avatar (sometimes avatara) is an incarnation of the divine on earth. Examples include Babaji, Krishna, and Christ. The word means “descent,” and Yogananda states, “In the Hindu scriptures, avatara signifies the descent of Divinity into flesh” (332).

Bhakti means devotion. It is one of the main paths to God and is the path followed by Yogananda.