Brahmavidya is a generic word, which is a combination of two words, Brahma + Vidya. Brahma is the term used in ancient Sanskrit philosophical literature to denote the Supreme Being, which is commonly called as God, Ishwar, Bhagwan. Hence Brahmavidya is a teaching telling us about Brahma – God, God’s way, God’s Order. This is the philosophical or theoretical part elaborating upon reality of life, the truth of existence.
With above definition, all scriptures of various religions, telling us about God and God’s order is Brahmavidya. All 18 chapters of the Geeta is Brahmavidya. At the end of every chapter of Geeta the name of the Yoga technique of that chapter is mentioned.